Standard procedure for songs in jazz gigs is to play the head for the first chorus, improvise over a number of choruses then "head out", which means repeat the head through the last chorus. Real Tracks styles do this great as the bass "walks" on the middle choruses for most jazz styles.

sometimes things change during a gig so it would be great to simply add or subtract choruses while the song is playing. Conductor does this fine for styles totally midi but does not work reliably for styles using Real Tracks.