Is this on a symmetric or asymmetric ball? There are a couple of factors at play here. One is the reaction of the MB in this position or rather distance from PAP and the other is drill depth of the thumb hole itself. One would have to drill the thumb hole deep enough to alter the core in some way - which would affect the differential - otherwise you would not get much in the way of increased dynamics as seen in data using a gradient weight hole. If the ball has a strong MB, it's hard to know who to believe. Ebonite claims that balls with a strong MB and the MB being greater than 5-1/2" from PAP, then flare is reduced significantly.
Anyway, with the right ball, I think it would be a good experiment to try thumb on MB and RF on Pin to MB line. It would probably work best with a 4-5" pin so you can drill the thumb hole deeper.
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Warmon - when all you have is a hammer, everything looks like a nail
