I just tried it, and couldn’t get it to work, but i did manage to link the video in a sequence to a selected auto synced clip in a bin. (it linked the video, but not the audio…audio stayed with the original audio), but this would allow you to autosync your clips, creating a new submaster with synced audio from the recorder.
Link your sequence to these clips based on name and timecode, all selected clips in open bins…(make sure all your new sync clips are selected.
Then, you have a sequence where the video comes from 1 source, and the audio from another source.
(video from the newly synced clips, audio from the original quicktime source)
Match frame each video shot in the timeline, patch the audio in, and replace edit. (If you had the proper equipment, you could even build a macro to do the entire timeline with the push of 1 button) In your case, learing some shortcut keys could probably get you through a moderate sized timeline without too much stress.
As for future custom columns, you would go to list view in your bin, right click in one of the column names and select custom column. You can then make a column named anything you like. Save that view setting, and open it up in the bin that contains your sequence. Now when doing a relink, you can select that custom column name as a source to relink via.
good luck.
Glenn