diff --git a/lib/widgets/question_source_settings_sheet.dart b/lib/widgets/question_source_settings_sheet.dart
index cce1ec3..4c1be53 100644
--- a/lib/widgets/question_source_settings_sheet.dart
+++ b/lib/widgets/question_source_settings_sheet.dart
@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 
 import '../models/question_source_preference.dart';
 import '../repositories/question_source_config_repository.dart';
@@ -53,9 +54,191 @@ class _QuestionSourceSettingsSheetState extends State<QuestionSourceSettingsShee
     ).map((QuestionSourcePreference source) => source.copyWith()).toList();
   }
 
-  void _updateSource(int index, QuestionSourcePreference next) {
+  List<int> _distribute(List<double> targetProportions, int targetSum) {
+    final List<double> values = targetProportions.map((double p) => p * targetSum).toList();
+    final List<int> floorValues = values.map((double v) => v.floor()).toList();
+    final int currentSum = floorValues.fold(0, (int sum, int val) => sum + val);
+    final int remainder = targetSum - currentSum;
+
+    if (remainder > 0) {
+      final List<int> indices = List<int>.generate(values.length, (int i) => i);
+      indices.sort((int a, int b) {
+        final double fracA = values[a] - floorValues[a];
+        final double fracB = values[b] - floorValues[b];
+        return fracB.compareTo(fracA);
+      });
+
+      for (int i = 0; i < remainder; i++) {
+        floorValues[indices[i % indices.length]] += 1;
+      }
+    }
+    return floorValues;
+  }
+
+  void _updateRatio(int targetIndex, int newRatio) {
     setState(() {
-      _draft[index] = next;
+      newRatio = newRatio.clamp(0, 100);
+      
+      if (newRatio == 100) {
+        for (int i = 0; i < _draft.length; i++) {
+          if (i == targetIndex) {
+            _draft[i] = _draft[i].copyWith(enabled: true, ratio: 100);
+          } else {
+            _draft[i] = _draft[i].copyWith(enabled: false, ratio: 0);
+          }
+        }
+        _validationMessage = null;
+        return;
+      }
+
+      final List<MapEntry<int, QuestionSourcePreference>> otherActiveSources = _draft
+          .asMap()
+          .entries
+          .where((MapEntry<int, QuestionSourcePreference> entry) =>
+              entry.key != targetIndex &&
+              !entry.value.comingSoon &&
+              entry.value.enabled)
+          .toList();
+      
+      if (otherActiveSources.isEmpty) {
+        final List<int> disabledNonComingSoonIndices = _draft
+            .asMap()
+            .entries
+            .where((MapEntry<int, QuestionSourcePreference> entry) =>
+                entry.key != targetIndex && !entry.value.comingSoon)
+            .map((MapEntry<int, QuestionSourcePreference> entry) => entry.key)
+            .toList();
+
+        if (disabledNonComingSoonIndices.isNotEmpty) {
+          final int freedPercentage = 100 - newRatio;
+          final List<double> proportions = List<double>.filled(
+            disabledNonComingSoonIndices.length,
+            1.0 / disabledNonComingSoonIndices.length,
+          );
+          final List<int> distributed = _distribute(proportions, freedPercentage);
+
+          _draft[targetIndex] = _draft[targetIndex].copyWith(enabled: true, ratio: newRatio);
+          for (int i = 0; i < disabledNonComingSoonIndices.length; i++) {
+            final int idx = disabledNonComingSoonIndices[i];
+            _draft[idx] = _draft[idx].copyWith(enabled: true, ratio: distributed[i]);
+          }
+        } else {
+          _draft[targetIndex] = _draft[targetIndex].copyWith(enabled: true, ratio: 100);
+        }
+        _validationMessage = null;
+        return;
+      }
+
+      final int targetOtherSum = 100 - newRatio;
+      final int currentOtherSum = otherActiveSources.fold<int>(
+        0,
+        (int sum, MapEntry<int, QuestionSourcePreference> entry) => sum + entry.value.ratio,
+      );
+
+      final List<int> otherIndices = otherActiveSources.map((MapEntry<int, QuestionSourcePreference> entry) => entry.key).toList();
+      final List<double> proportions = <double>[];
+      if (currentOtherSum > 0) {
+        for (final int idx in otherIndices) {
+          proportions.add(_draft[idx].ratio / currentOtherSum);
+        }
+      } else {
+        for (int i = 0; i < otherIndices.length; i++) {
+          proportions.add(1.0 / otherIndices.length);
+        }
+      }
+
+      final List<int> distributed = _distribute(proportions, targetOtherSum);
+      
+      _draft[targetIndex] = _draft[targetIndex].copyWith(enabled: true, ratio: newRatio);
+      for (int i = 0; i < otherIndices.length; i++) {
+        final int idx = otherIndices[i];
+        _draft[idx] = _draft[idx].copyWith(ratio: distributed[i]);
+      }
+      _validationMessage = null;
+    });
+  }
+
+  void _toggleSourceEnabled(int targetIndex, bool enabled) {
+    setState(() {
+      if (enabled) {
+        final List<int> otherActiveIndices = _draft
+            .asMap()
+            .entries
+            .where((MapEntry<int, QuestionSourcePreference> entry) =>
+                entry.key != targetIndex &&
+                !entry.value.comingSoon &&
+                entry.value.enabled)
+            .map((MapEntry<int, QuestionSourcePreference> entry) => entry.key)
+            .toList();
+
+        if (otherActiveIndices.isEmpty) {
+          _draft[targetIndex] = _draft[targetIndex].copyWith(enabled: true, ratio: 100);
+        } else {
+          final int newCount = otherActiveIndices.length + 1;
+          final int targetRatio = (100 / newCount).round();
+          final int remainingRatio = 100 - targetRatio;
+
+          final int currentOtherSum = otherActiveIndices.fold<int>(
+            0,
+            (int sum, int idx) => sum + _draft[idx].ratio,
+          );
+
+          final List<double> proportions = <double>[];
+          if (currentOtherSum > 0) {
+            for (final int idx in otherActiveIndices) {
+              proportions.add(_draft[idx].ratio / currentOtherSum);
+            }
+          } else {
+            for (int i = 0; i < otherActiveIndices.length; i++) {
+              proportions.add(1.0 / otherActiveIndices.length);
+            }
+          }
+
+          final List<int> distributed = _distribute(proportions, remainingRatio);
+          
+          _draft[targetIndex] = _draft[targetIndex].copyWith(enabled: true, ratio: targetRatio);
+          for (int i = 0; i < otherActiveIndices.length; i++) {
+            final int idx = otherActiveIndices[i];
+            _draft[idx] = _draft[idx].copyWith(ratio: distributed[i]);
+          }
+        }
+      } else {
+        _draft[targetIndex] = _draft[targetIndex].copyWith(enabled: false, ratio: 0);
+
+        final List<int> otherActiveIndices = _draft
+            .asMap()
+            .entries
+            .where((MapEntry<int, QuestionSourcePreference> entry) =>
+                entry.key != targetIndex &&
+                !entry.value.comingSoon &&
+                entry.value.enabled)
+            .map((MapEntry<int, QuestionSourcePreference> entry) => entry.key)
+            .toList();
+
+        if (otherActiveIndices.isNotEmpty) {
+          final int currentOtherSum = otherActiveIndices.fold<int>(
+            0,
+            (int sum, int idx) => sum + _draft[idx].ratio,
+          );
+
+          final List<double> proportions = <double>[];
+          if (currentOtherSum > 0) {
+            for (final int idx in otherActiveIndices) {
+              proportions.add(_draft[idx].ratio / currentOtherSum);
+            }
+          } else {
+            for (int i = 0; i < otherActiveIndices.length; i++) {
+              proportions.add(1.0 / otherActiveIndices.length);
+            }
+          }
+
+          final List<int> distributed = _distribute(proportions, 100);
+          for (int i = 0; i < otherActiveIndices.length; i++) {
+            final int idx = otherActiveIndices[i];
+            _draft[idx] = _draft[idx].copyWith(ratio: distributed[i]);
+          }
+        }
+      }
       _validationMessage = null;
     });
   }
@@ -197,8 +380,8 @@ class _QuestionSourceSettingsSheetState extends State<QuestionSourceSettingsShee
                       key: Key('question-source-row-${_draft[index].id}'),
                       source: _draft[index],
                       effectivePercent: mix[_draft[index].id],
-                      onChanged: (QuestionSourcePreference next) =>
-                          _updateSource(index, next),
+                      onRatioChanged: (int ratio) => _updateRatio(index, ratio),
+                      onEnabledChanged: (bool enabled) => _toggleSourceEnabled(index, enabled),
                       onEditSpelling: _draft[index].id == 'spelling'
                           ? () => _openSpellingWordList(context)
                           : null,
@@ -281,12 +464,13 @@ class _QuestionSourceSettingsSheetState extends State<QuestionSourceSettingsShee
   }
 }
 
-class _QuestionSourceRow extends StatelessWidget {
+class _QuestionSourceRow extends StatefulWidget {
   const _QuestionSourceRow({
     super.key,
     required this.source,
     required this.effectivePercent,
-    required this.onChanged,
+    required this.onRatioChanged,
+    required this.onEnabledChanged,
     this.onEditSpelling,
     this.onResetSpelling,
     this.resetSpellingBusy = false,
@@ -294,11 +478,73 @@ class _QuestionSourceRow extends StatelessWidget {
 
   final QuestionSourcePreference source;
   final int? effectivePercent;
-  final ValueChanged<QuestionSourcePreference> onChanged;
+  final ValueChanged<int> onRatioChanged;
+  final ValueChanged<bool> onEnabledChanged;
   final VoidCallback? onEditSpelling;
   final VoidCallback? onResetSpelling;
   final bool resetSpellingBusy;
 
+  @override
+  State<_QuestionSourceRow> createState() => _QuestionSourceRowState();
+}
+
+class _QuestionSourceRowState extends State<_QuestionSourceRow> {
+  late final TextEditingController _controller;
+  late final FocusNode _focusNode;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = TextEditingController(text: '${widget.source.ratio}');
+    _focusNode = FocusNode();
+    _focusNode.addListener(_onFocusChange);
+  }
+
+  @override
+  void didUpdateWidget(covariant _QuestionSourceRow oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.source.ratio != widget.source.ratio) {
+      final int? parsed = int.tryParse(_controller.text);
+      if (parsed != widget.source.ratio) {
+        if (_controller.text.isEmpty && widget.source.ratio == 0) {
+          return;
+        }
+        _controller.text = '${widget.source.ratio}';
+      }
+    }
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    _focusNode.removeListener(_onFocusChange);
+    _focusNode.dispose();
+    super.dispose();
+  }
+
+  void _onFocusChange() {
+    if (!_focusNode.hasFocus) {
+      if (_controller.text.isEmpty) {
+        _controller.text = '0';
+        widget.onRatioChanged(0);
+      }
+    }
+  }
+
+  void _onTextChange(String text) {
+    if (text.isEmpty) {
+      widget.onRatioChanged(0);
+      return;
+    }
+    final int? value = int.tryParse(text);
+    if (value != null) {
+      final int clamped = value.clamp(0, 100);
+      if (clamped != widget.source.ratio) {
+        widget.onRatioChanged(clamped);
+      }
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return Padding(
@@ -324,11 +570,11 @@ class _QuestionSourceRow extends StatelessWidget {
                           children: <Widget>[
                             Flexible(
                               child: Text(
-                                source.label,
+                                widget.source.label,
                                 style: Theme.of(context).textTheme.titleLarge,
                               ),
                             ),
-                            if (source.comingSoon) ...<Widget>[
+                            if (widget.source.comingSoon) ...<Widget>[
                               const SizedBox(width: 8),
                               DecoratedBox(
                                 decoration: BoxDecoration(
@@ -358,61 +604,116 @@ class _QuestionSourceRow extends StatelessWidget {
                         ),
                         const SizedBox(height: 2),
                         Text(
-                          source.description,
+                          widget.source.description,
                           style: Theme.of(context).textTheme.bodyLarge,
                         ),
                       ],
                     ),
                   ),
-                  if (onEditSpelling != null)
+                  if (widget.onEditSpelling != null)
                     IconButton(
                       key: const Key('question-source-edit-spelling'),
                       tooltip: 'Edit spelling word list',
-                      onPressed: resetSpellingBusy ? null : onEditSpelling,
+                      onPressed: widget.resetSpellingBusy ? null : widget.onEditSpelling,
                       icon: const Icon(Icons.edit, size: 20),
                     ),
-                  if (onResetSpelling != null)
+                  if (widget.onResetSpelling != null)
                     IconButton(
                       key: const Key('question-source-reset-spelling'),
                       tooltip: 'Reset spelling progress',
-                      onPressed: resetSpellingBusy ? null : onResetSpelling,
+                      onPressed: widget.resetSpellingBusy ? null : widget.onResetSpelling,
                       icon: const Icon(Icons.restart_alt, size: 20),
                     ),
                   Switch(
-                    key: Key('question-source-enabled-${source.id}'),
-                    value: source.enabled,
-                    onChanged: source.comingSoon
+                    key: Key('question-source-enabled-${widget.source.id}'),
+                    value: widget.source.enabled,
+                    onChanged: widget.source.comingSoon
                         ? null
-                        : (bool enabled) =>
-                            onChanged(source.copyWith(enabled: enabled)),
+                        : (bool enabled) => widget.onEnabledChanged(enabled),
                   ),
                 ],
               ),
-              if (source.enabled && !source.comingSoon) ...<Widget>[
+              if (widget.source.enabled && !widget.source.comingSoon) ...<Widget>[
                 Row(
                   children: <Widget>[
                     const Text('Weight'),
                     const Spacer(),
-                    Text(
-                      effectivePercent == null
-                          ? '${source.ratio}'
-                          : '${source.ratio} (${effectivePercent}%)',
-                      style: const TextStyle(
-                        color: AppColors.accent,
-                        fontWeight: FontWeight.w600,
+                    SizedBox(
+                      width: 70,
+                      height: 36,
+                      child: TextField(
+                        key: Key('question-source-input-${widget.source.id}'),
+                        controller: _controller,
+                        focusNode: _focusNode,
+                        keyboardType: TextInputType.number,
+                        textAlign: TextAlign.center,
+                        style: const TextStyle(
+                          color: AppColors.accent,
+                          fontWeight: FontWeight.w600,
+                          fontSize: 14,
+                        ),
+                        decoration: InputDecoration(
+                          contentPadding: const EdgeInsets.symmetric(
+                            horizontal: 6,
+                            vertical: 8,
+                          ),
+                          suffixText: '%',
+                          suffixStyle: const TextStyle(
+                            color: AppColors.accent,
+                            fontWeight: FontWeight.w600,
+                            fontSize: 14,
+                          ),
+                          border: OutlineInputBorder(
+                            borderRadius: BorderRadius.circular(6),
+                            borderSide: const BorderSide(
+                              color: AppColors.accent,
+                            ),
+                          ),
+                          enabledBorder: OutlineInputBorder(
+                            borderRadius: BorderRadius.circular(6),
+                            borderSide: BorderSide(
+                              color: AppColors.accent.withValues(alpha: 0.3),
+                            ),
+                          ),
+                          focusedBorder: OutlineInputBorder(
+                            borderRadius: BorderRadius.circular(6),
+                            borderSide: const BorderSide(
+                              color: AppColors.accent,
+                            ),
+                          ),
+                        ),
+                        inputFormatters: <TextInputFormatter>[
+                          FilteringTextInputFormatter.digitsOnly,
+                        ],
+                        onChanged: (String text) {
+                          final int? val = int.tryParse(text);
+                          if (val != null) {
+                            if (val > 100) {
+                              _controller.text = '100';
+                              _controller.selection = TextSelection.fromPosition(
+                                const TextPosition(offset: 3),
+                              );
+                              widget.onRatioChanged(100);
+                            } else {
+                              _onTextChange(text);
+                            }
+                          } else {
+                            _onTextChange(text);
+                          }
+                        },
                       ),
                     ),
                   ],
                 ),
                 Slider(
-                  key: Key('question-source-ratio-${source.id}'),
-                  value: source.ratio.toDouble(),
+                  key: Key('question-source-ratio-${widget.source.id}'),
+                  value: widget.source.ratio.toDouble(),
                   min: 0,
                   max: 100,
-                  divisions: 20,
-                  label: '${source.ratio}',
+                  divisions: 100,
+                  label: '${widget.source.ratio}',
                   onChanged: (double value) =>
-                      onChanged(source.copyWith(ratio: value.round())),
+                      widget.onRatioChanged(value.round()),
                 ),
               ],
             ],
diff --git a/server/lib/handlers/questions_handler.dart b/server/lib/handlers/questions_handler.dart
index 5576835..d923d11 100644
--- a/server/lib/handlers/questions_handler.dart
+++ b/server/lib/handlers/questions_handler.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ -147,6 +148,7 @@ Handler questionsHandler({
               (nextQuestion['unansweredCount'] as num?)?.toInt() ??
                   unansweredCount;
         }
+        unawaited(questionDispatcher.topUpQueue(firebaseUid));
         final bool isMarketAnswer =
             QuestionsDb.resolveSourceId(updated) == 'market_history';
         final Map<String, dynamic>? score = isMarketAnswer
@@ -232,6 +234,7 @@ Handler questionsHandler({
           firebaseUid: firebaseUid,
           deferredQuestionId: id,
         );
+        unawaited(questionDispatcher.topUpQueue(firebaseUid));
         return _jsonResponse(200, <String, dynamic>{
           'question': updated,
           'unansweredCount': unansweredCount,
diff --git a/server/lib/pipeline/question_pipeline.dart b/server/lib/pipeline/question_pipeline.dart
index ae9a1e3..d6a1295 100644
--- a/server/lib/pipeline/question_pipeline.dart
+++ b/server/lib/pipeline/question_pipeline.dart
@@ -496,6 +496,11 @@ class QuestionPipeline {
     await _startSpellingPipeline(firebaseUid);
   }
 
+  /// Force enqueues a new spelling question (e.g. after a deferral).
+  Future<void> forceEnqueueSpellingQuestion(String firebaseUid) async {
+    await _startSpellingPipeline(firebaseUid, force: true);
+  }
+
   Future<Map<String, dynamic>> _loadContext(
     String firebaseUid,
     String pipelineKey,
diff --git a/server/lib/question_dispatcher.dart b/server/lib/question_dispatcher.dart
index 69fb181..029aba5 100644
--- a/server/lib/question_dispatcher.dart
+++ b/server/lib/question_dispatcher.dart
@@ -104,25 +104,12 @@ class QuestionDispatcher {
     required Map<String, dynamic> answeredQuestion,
   }) async {
     _log('nextQuestionAfterAnswer($firebaseUid)');
-    final String answeredSourceId = QuestionsDb.resolveSourceId(answeredQuestion);
-
     var rows = await _listEnabledUnansweredOrdered(firebaseUid);
     if (rows.isEmpty) {
       _log('Queue empty, falling back to dispatchNextQuestion');
       return dispatchNextQuestion(firebaseUid);
     }
 
-    // Pipeline continuity: If we just answered a spelling question and another
-    // spelling question is available (e.g. follow-up or next word quiz), return it
-    // immediately. Pipelines should not be interrupted by mix changes.
-    if (answeredSourceId == 'spelling') {
-      for (final Map<String, dynamic> row in rows) {
-        if (QuestionsDb.resolveSourceId(row) == 'spelling') {
-          return _toClientPayload(row, rows.length);
-        }
-      }
-    }
-
     final List<ResolvedQuestionSourcePreference> prefs =
         await _preferencesDb.getResolved(firebaseUid);
     final Map<String, int> mix = QuestionSourceMix.effectiveMixFromResolved(prefs);
@@ -150,17 +137,49 @@ class QuestionDispatcher {
     required String firebaseUid,
     required String deferredQuestionId,
   }) async {
+    final List<ResolvedQuestionSourcePreference> prefs =
+        await _preferencesDb.getResolved(firebaseUid);
+    final Map<String, int> mix = QuestionSourceMix.effectiveMixFromResolved(prefs);
+    final Map<String, int> delivered =
+        await _questionsDb.countDeliveredBySourceId(firebaseUid);
+
+    final String preferred = QuestionSourceMix.pickNextSourceId(
+      effectiveMixPercent: mix,
+      deliveredCounts: delivered,
+      random: _random,
+    );
+
+    // If spelling was rolled/preferred, but the only spelling question is the deferred one,
+    // force enqueue a new spelling question (so the user gets a different word).
+    if (preferred == 'spelling') {
+      final List<Map<String, dynamic>> currentRows =
+          await _listEnabledUnansweredOrdered(firebaseUid);
+      final bool hasOtherSpelling = currentRows.any((Map<String, dynamic> row) =>
+          QuestionsDb.resolveSourceId(row) == 'spelling' &&
+          row['id'] != deferredQuestionId);
+      if (!hasOtherSpelling && QuestionSourcePreferences.isEnabled(prefs, 'spelling')) {
+        await _questionPipeline.forceEnqueueSpellingQuestion(firebaseUid);
+      }
+    }
+
     final List<Map<String, dynamic>> rows =
         await _listEnabledUnansweredOrdered(firebaseUid);
     if (rows.isEmpty) {
       return dispatchNextQuestion(firebaseUid);
     }
-    for (final Map<String, dynamic> row in rows) {
+
+    final List<Map<String, dynamic>> ordered =
+        QuestionSourceMix.orderUnansweredByPreferredSource(
+      rows,
+      preferredSourceId: preferred,
+    );
+
+    for (final Map<String, dynamic> row in ordered) {
       if (row['id'] != deferredQuestionId) {
         return _toClientPayload(row, rows.length);
       }
     }
-    return _toClientPayload(rows.first, rows.length);
+    return _toClientPayload(ordered.first, rows.length);
   }
 
   /// Fills the queue up to [maxQueuedQuestions] using mix-sequential source picks.
diff --git a/server/test/integration/spelling_only_panel_test.dart b/server/test/integration/spelling_only_panel_test.dart
index 7738fc0..77bf387 100644
--- a/server/test/integration/spelling_only_panel_test.dart
+++ b/server/test/integration/spelling_only_panel_test.dart
@@ -1,8 +1,9 @@
 @Tags(<String>['integration', 'postgres'])
 library;
 
+import 'dart:math';
+
 import 'package:cyberhybridhub_server/question_dispatcher.dart';
-import 'package:cyberhybridhub_server/questions_db.dart';
 import 'package:test/test.dart';
 
 import '../helpers/test_db.dart';
@@ -145,4 +146,153 @@ void main() {
     expect(panel.first['sourceId'], 'spelling');
     expect(panel.first['presentation'], 'spelling_word');
   });
+
+  test('nextQuestionAfterAnswer respects random roll for spelling mix when spelling is 50%',
+      () async {
+    if (testDb == null) {
+      markTestSkipped('Set DATABASE_URL or TEST_DATABASE_URL for integration tests');
+      return;
+    }
+
+    const String uid = 'spelling-50-next-answer-uid';
+    await testDb!.seedUser(uid);
+    await testDb!.questionSourcePreferencesDb.save(
+      uid,
+      <Map<String, dynamic>>[
+        <String, dynamic>{'id': 'market_history', 'enabled': true, 'ratio': 50},
+        <String, dynamic>{'id': 'spelling', 'enabled': true, 'ratio': 50},
+      ],
+    );
+
+    // Create a market question and a spelling question.
+    await testDb!.questionsDb.createQuestion(
+      assignedUserId: uid,
+      questionText: 'Market question',
+      correctAnswer: 5,
+      sourceTag: 'market_history:prospective',
+      pipelineKey: 'trading',
+    );
+    await testDb!.questionsDb.createQuestion(
+      assignedUserId: uid,
+      questionText: 'Spelling question',
+      correctAnswer: 0,
+      sourceTag: 'spelling:word_quiz',
+      pipelineKey: 'spelling',
+      pipelineStep: 'spelling_word_quiz',
+    );
+
+    // Set up a custom mock Random where nextInt(100) returns 80 (which is >= 50, so spelling).
+    final QuestionDispatcher spellingFavoredDispatcher = testDb!.questionDispatcher(
+      random: _SequentialRandom(<int>[80]),
+    );
+
+    // Set up a custom mock Random where the first nextInt(100) returns 80 (prefers spelling ordering)
+    // and the second nextInt(100) returns 10 (< 50, selecting market_history).
+    final QuestionDispatcher marketFavoredDispatcher = testDb!.questionDispatcher(
+      random: _SequentialRandom(<int>[80, 10]),
+    );
+
+    final Map<String, dynamic> fakeAnswered = <String, dynamic>{
+      'sourceTag': 'spelling:word_quiz',
+      'pipelineKey': 'spelling',
+      'pipelineStep': 'spelling_word_quiz',
+    };
+
+    // When roll is 10 (spelling favored): next should be spelling question.
+    final Map<String, dynamic>? nextSpelling = await spellingFavoredDispatcher.nextQuestionAfterAnswer(
+      firebaseUid: uid,
+      answeredQuestion: fakeAnswered,
+    );
+    expect(nextSpelling, isNotNull);
+    expect(nextSpelling!['sourceId'], 'spelling');
+
+    // When roll is 80 (market/mix favored): next should be market question (since it's at the head).
+    final Map<String, dynamic>? nextMarket = await marketFavoredDispatcher.nextQuestionAfterAnswer(
+      firebaseUid: uid,
+      answeredQuestion: fakeAnswered,
+    );
+    expect(nextMarket, isNotNull);
+    expect(nextMarket!['sourceId'], 'market_history');
+  });
+
+  test('nextQuestionAfterDefer respects mix roll and enqueues new spelling if spelling is rolled',
+      () async {
+    if (testDb == null) {
+      markTestSkipped('Set DATABASE_URL or TEST_DATABASE_URL for integration tests');
+      return;
+    }
+
+    const String uid = 'spelling-50-defer-uid';
+    await testDb!.seedUser(uid);
+    await testDb!.questionSourcePreferencesDb.save(
+      uid,
+      <Map<String, dynamic>>[
+        <String, dynamic>{'id': 'market_history', 'enabled': true, 'ratio': 50},
+        <String, dynamic>{'id': 'spelling', 'enabled': true, 'ratio': 50},
+      ],
+    );
+
+    // Create a market question and a spelling question.
+    await testDb!.questionsDb.createQuestion(
+      assignedUserId: uid,
+      questionText: 'Market question',
+      correctAnswer: 5,
+      sourceTag: 'market_history:prospective',
+      pipelineKey: 'trading',
+    );
+    final Map<String, dynamic> spellingQ = await testDb!.questionsDb.createQuestion(
+      assignedUserId: uid,
+      questionText: 'Spelling question',
+      correctAnswer: 0,
+      sourceTag: 'spelling:word_quiz',
+      pipelineKey: 'spelling',
+      pipelineStep: 'spelling_word_quiz',
+    );
+
+    // spellingFavoredDispatcher rolls 80 (>= 50), which selects spelling.
+    final QuestionDispatcher spellingFavoredDispatcher = testDb!.questionDispatcher(
+      random: _SequentialRandom(<int>[80]),
+    );
+
+    // marketFavoredDispatcher rolls 10 (< 50), which selects market_history.
+    final QuestionDispatcher marketFavoredDispatcher = testDb!.questionDispatcher(
+      random: _SequentialRandom(<int>[10]),
+    );
+
+    // 1. When spelling is rolled: next should be a NEW spelling question.
+    final Map<String, dynamic>? nextSpelling = await spellingFavoredDispatcher.nextQuestionAfterDefer(
+      firebaseUid: uid,
+      deferredQuestionId: spellingQ['id'] as String,
+    );
+    expect(nextSpelling, isNotNull);
+    expect(nextSpelling!['sourceId'], 'spelling');
+    expect(nextSpelling['id'], isNot(spellingQ['id'])); // Verifies it is a new question
+
+    // 2. When market is rolled: next should be the market question.
+    final Map<String, dynamic>? nextMarket = await marketFavoredDispatcher.nextQuestionAfterDefer(
+      firebaseUid: uid,
+      deferredQuestionId: spellingQ['id'] as String,
+    );
+    expect(nextMarket, isNotNull);
+    expect(nextMarket!['sourceId'], 'market_history');
+  });
+}
+
+class _SequentialRandom implements Random {
+  _SequentialRandom(this._values);
+  final List<int> _values;
+  int _index = 0;
+
+  @override
+  int nextInt(int max) {
+    final int val = _values[_index % _values.length];
+    _index++;
+    return val;
+  }
+
+  @override
+  bool nextBool() => false;
+
+  @override
+  double nextDouble() => 0.0;
 }
diff --git a/test/question_source_settings_test.dart b/test/question_source_settings_test.dart
index 2f4c356..a145630 100644
--- a/test/question_source_settings_test.dart
+++ b/test/question_source_settings_test.dart
@@ -188,4 +188,88 @@ void main() {
     await tester.pumpAndSettle();
     expect(find.byKey(const Key('question-source-config-top-bar')), findsNothing);
   });
+
+  testWidgets('proportional slider balancing and manual text inputs', (
+    WidgetTester tester,
+  ) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: buildAppTheme(),
+        home: const HomeScreen(
+          user: AppUser(uid: 'u1', displayName: 'Test User'),
+        ),
+      ),
+    );
+
+    // Open configuration dialog.
+    await tester.tap(find.byKey(const Key('question-source-settings-button')));
+    await tester.pumpAndSettle();
+
+    // Verify initial state: both sources enabled and ratio is 50.
+    final Finder marketInput = find.byKey(const Key('question-source-input-market_history'));
+    final Finder spellingInput = find.byKey(const Key('question-source-input-spelling'));
+    
+    expect(marketInput, findsOneWidget);
+    expect(spellingInput, findsOneWidget);
+    
+    expect(tester.widget<TextField>(marketInput).controller?.text, '50');
+    expect(tester.widget<TextField>(spellingInput).controller?.text, '50');
+
+    // 1. Enter 80 in market_history input.
+    await tester.enterText(marketInput, '80');
+    await tester.pumpAndSettle();
+
+    // Verify spelling proportionally reduced to 20.
+    expect(tester.widget<TextField>(marketInput).controller?.text, '80');
+    expect(tester.widget<TextField>(spellingInput).controller?.text, '20');
+
+    // 2. Put market_history to 100.
+    await tester.enterText(marketInput, '100');
+    await tester.pumpAndSettle();
+
+    // Verify spelling is auto-disabled.
+    final Switch spellingSwitch = tester.widget<Switch>(
+      find.byKey(const Key('question-source-enabled-spelling')),
+    );
+    expect(spellingSwitch.value, isFalse);
+    expect(find.byKey(const Key('question-source-input-spelling')), findsNothing);
+
+    // 3. Reduce market_history to 70.
+    await tester.enterText(marketInput, '70');
+    await tester.pumpAndSettle();
+
+    // Verify spelling auto-enabled and gets 30%.
+    final Switch spellingSwitchAfter = tester.widget<Switch>(
+      find.byKey(const Key('question-source-enabled-spelling')),
+    );
+    expect(spellingSwitchAfter.value, isTrue);
+    expect(find.byKey(const Key('question-source-input-spelling')), findsOneWidget);
+    expect(tester.widget<TextField>(find.byKey(const Key('question-source-input-spelling'))).controller?.text, '30');
+
+    // 4. Manually disable spelling.
+    await tester.tap(find.byKey(const Key('question-source-enabled-spelling')));
+    await tester.pumpAndSettle();
+
+    // Verify spelling is disabled and market_history automatically becomes 100%.
+    expect(tester.widget<TextField>(marketInput).controller?.text, '100');
+
+    // 5. Manually enable spelling.
+    await tester.tap(find.byKey(const Key('question-source-enabled-spelling')));
+    await tester.pumpAndSettle();
+
+    // Verify spelling gets enabled and shares the ratio evenly (50/50).
+    expect(tester.widget<TextField>(marketInput).controller?.text, '50');
+    expect(tester.widget<TextField>(find.byKey(const Key('question-source-input-spelling'))).controller?.text, '50');
+
+    // 6. Enter a value > 100 (e.g. 150) in market_history input.
+    await tester.enterText(marketInput, '150');
+    await tester.pumpAndSettle();
+
+    // Verify it clamps to 100.
+    expect(tester.widget<TextField>(marketInput).controller?.text, '100');
+    
+    // Close dialog.
+    await tester.tap(find.byKey(const Key('question-source-settings-close')));
+    await tester.pumpAndSettle();
+  });
 }