To my knowledge, you have no control over what RTs produces. The fills, pushes and shots in RDs are defined in their .txt files found within the RD directory. Customizing RDs can be found in the BIAB manual. I've done a bit of customizing and can probably help if you decide to go this route. With the fills issue, play around with your part markers.

And if you get a track sounding 'right', don't forget to Freeze it. If not, each time you press Play, the track will regenerate (except Melody and Soloist).

R