Noel -- I wasn't able to play your second file, because it crashed my program. I don't know why, since your first file ran just fine. Given Kent's comment, I'm becoming increasingly convinced the BIAB is not happy running on a Mac. Nonetheless, the structure you used with the four intro bars is one I use all the time, so I'm familiar with it.

As for laying out tunes as one long chorus rather than repeating choruses, I just don't know the correct approach. The program seemingly wants you to use repeating choruses and provides a wide assortment of tools (eg., jumps, sections, first/ second endings, etc) that make traditional composition possible. It certainly make printing chord sheets a lot easier. On the other hand, the way the program manages soloists makes such a layout challenging. I haven't landed on a comfortable approach.