With my current grip, I feel I just can't get around the ball and get the rotation on the ball that I would like.  I'm thinking about going more forward in the fingers.  I know the trend is to go more reverse in the fingers and forward in the thumb, but  I've tried more forward in the thumb and I just tend to hang up.  Is there a certain amount of forward in the fingers for a given span or thumb pitch? 

Current grip. Right handed, span is accurate, but with a relaxed un-stretched grip.

Middle  0 L/R, 1/8 reverse, span 4 3/4, use looser inserts
Ring     3/4 R, 1/8 reverse, span 4 3/4, use looser inserts
Thumb 3/4 R, 3/16 reverse, Use a tight thumb hole, thumb on the long side.

I know 3/4 right in the thumb is extreme. My thumb hinges pretty much across my palm and points beyond my pinky when doing the coke can grip test.

Any help is appreciated.  Or if you know the best fitter in the nation I will fly there to have them fit me.

I use finger straightness and relation to thumb pitch to determine a starting point for lateral finger pitches.  Unless you had unusually crooked fingers you will probably be uncomfortable and/or tear up your hand using 3/4 left while using 3/4 right in your thumb.  The 3/4 right you currently use is probably fine as long as your fingers are relatively straight and this doesn't create pressure on them as you are using that much lateral in the thumb.

I was thinking of trying 3/4 left middle and 0 ring and then putting the thumb at 0, just to see what it did to my roll and rotation.

Well I went to 1/8 forward in both fingers and reduced the ring finger span a bit.  I also went to one size tighter inserts. I think these changes are really helping.  I feel I can hold onto the ball a lot better.  I feel I can be aggressive with my speed and get plenty of hand where the ball will still hook. I feel that this also relieved some of the pressure on my index finger.  Hopefully I don't develop any other issues because of the pitch changes.