I would lust leave them separate as Biab will read all the SGU in one go. Yes you can add more anytime as long as they are recorded the same. They can be random chord progression unless you have it playing over into another chord. The more material the better, like endings.

I made a usertrack with just a voice or you can do a voice over saying the current bar chord name, you can do that to see what chord is being transposed and say the SGU number to see what SGU is being used for testing purposes.