Also a relative newbie but here's a couple of thoughts.

First be sure your tracks aren't Frozen.
Click on the blue circular snowflake to see if any are checked.
Frozen tracks will stay the same each time you play them.

Another idea is to extend your songs with several chorus's as you may find more variations pop up per generation.
You could then Freeze the track and use the Drop feature to copy it to Realband or another DAW like Reaper or Audacity.

If you run out of tracks in BIAB you could save the song as My SOng 01, then regenerate and save as My Song 02 etc. Then try continuing by using the DAW Drop to get each part you liked from each song into Realband where you can generate and create up to 48 separate tracks.

A collection of these dropped tracks may be able to be stitched together to get what you want.

Check out a great video tutorial series by Dan where he takes you through his process and does this, very informative:
http://www.pgmusic.com/videos.user.htm

I'm sure you'll get more and better ideas from the veterans here in the Forum. They've helped me a lot and your input and their's helps PG improve their already amazing product.
Plus there's always the Wish List Forum where you can make suggestions.

Good luck and have fun learning,
Carl