The following is a link to a Ron Clifton article on finger position. Pretty clear explanation of what effect different finger positions have on the shape of the ball path.
http://www.bowl4fun.com/ron/tip11.htm
He doesn't go into detail on what the changes in finger position do to rev rate, axis tilt or axis rotation so I'm not sure that I'm helping with your specific questions, but then I really don't care what my rev rate is as long as can figure out how to get the ball in the pocket.
I think that keeping the index finger spread out but putting my pinkie finger against my ring finger without tucking it, would give you less revs. I say that only because you said,"I've tucked my pinkie in at the first knuckle to give it extra revs."
As for figuring out how to get a lower track, next time you practice experiment with different positions and see what happens to the track.
Bookmarks