As far as I can see, in qa-ajax-asktitle.php (line 40-42):
$relatedquestions=qa_db_select_with_pending(
qa_db_search_posts_selectspec(null, qa_string_to_words($intitle), null, null, null, null, 0, false, $countqs)
);
is retrieving the related questions for the ask title.
Now I would like to change this to use the general search algorithm, which I found in qa-widget-related-qs.php (line 53):
$questions=qa_db_single_select(qa_db_related_qs_selectspec($userid, $questionid, qa_opt('page_size_related_qs')));
How to replace the code above (qa-ajax-asktitle.php) with the other one without having userid? Would it work just to pass "null" for $userid?