I did this manually by copying and pasting the segments into a new track. This gives me more control but takes some time.
Is there any way this could be done automatically? 20 sec of a segment in any one of the above schemas.
Or if there is a faster way to do this myself than copy&paste?
Tracks are merged (mixed) just by being one above the other. So you could in fact retain two tracks and insert silences and repeats in each. Press F5 to time shift one track to start after the other, then F1 to go back to selection tool.