After poking around on Advmame's website, I was wondering the same thing. I'll have to check my video card (I think it is an ATI). I'm all-DOS, by the way (that is my purpose for trying advmame - to be able to play GT in DOS).
Paige, despite the fact that we don't NEED the space to roll, doesn't mean we don't WANT the space. In theory, a person could play using a thumb spin even if the monitor glass was vertical right above the trackball. But that doesn't mean we'd want to play it that way.

We used to play Shuuz fairly often, and we all made long, smooth strokes. It might not net a better effect or more accuracy, but it is more fun. I think it might be because the long stroke resembles the swinging sensation of throwing a horseshoe.
Wade