I don't have access to a camera right now, but I busted out a layout diagram in MS Paint real quick to see if anyone could figure out why my Tsunami tracks over the thumb. (Pin/CG in red, nugget in blue). I'd consider myself a power-tweener with medium speed. I stay behind the ball almost all the way through the swing with a little flick of the fingers at release if it helps.

http://mysite.verizon.net/res8ahda/tsunami_layout.JPG

Sorry for the quality, it looks like the ball saw a ghost. Anyway..

My Cobalts don't do it, and they are drilled label. Nothing special. The pin is about 2 1/2" on this ball, and I think it was 15.2 oz before drilling.

Would a weight hole on the side address it? I'm going to have my driller, who knows how I throw, take a look at the flaring on it. It goes over the hole pretty deep. My Cobalt Solid gets a little close to the thumb but never over it.
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Cobalt Bomb Solid
Cobalt Bomb Pearl
Tsunami H2O
F.O.S.

I would suggest trying to increase the side and finger weights to around 3/4 each. A hole on the track side of the ball will be necessary. Top weight may also need to be reduced if it's over 1 1/2 oz. now. Too much top and not enough side and/or finger weight can cause the track to pull up on the thumb. =:^D