I throw no thumb and bought a used Reaction Arc which I had redrilled.  The ball has the pin 1 1/2" from the CG so it's a pin-in ball.  It ended up flaring over the finger holes.  I'm considering having it redrilled with no thumbhole.  The idea is that it will allow the pin to be moved up into a more safe zone where the track won't flare over the finger holes, but because it has no thumbhole it will not have excessive finger weight.
I read the rules on no thumb drilling and it says the ball cannot have more than 1 oz top weight with no thumbhole, and the center of the bridge is considered the center of the grip.
I'm not sure of the top weight in this ball but it is probably more than 3 oz.
So I have a few questions:
If the fingers are drilled directly through the CG and very deep will it still have too much topweight?  Should I consider having a third fingerhole added?

Can you have a balance hole with no thumbhole and if so where would you put it?  Right below the fingerholes???  Is the balance hole considered a thumbhole and therefore your part of your hand must cover it?

Would I be better off having a thumbhole put in?  If I do, how far can I move the pin on this ball without ending up with too much finger weight?

Thanks in advance for any responses,
sprocket

The reason is that because it is a pin-in ball there may be more drilling options for pin placement without a thumbhole.  With a thumbhole the pin can only be moved up so far because the CG is moving with it.  Move it too far and it has excess finger weight.  Don't move it enough and the ball rolls over the finger holes.
I think it should be drilled with the pin right and slightly above the ring finger with the finger holes drilled through the CG or slightly left of the CG.
The question remains:  Can the fingerholes be drilled deep enough to remove the excess topweight?

The ball was drilled with the CG just right of the fingerholes and the pin about straight up from there.  The pin is around 4 1/2" from my PAP.  I must have been wrong about the top weight, it was actually pretty low.  It ended up with I think 3/4 oz top and some finger and side.  The holes weren't drilled very deep and no balance hole.  Of course no thumb either.
I'm not happy with the way it rolls.  It picks up a roll early and doesn't snap at all.  Unless I really play the oil it is a flat ten leaving machine.  I think it needs the surface shined up even more, like to 2000.
Thanks for all the suggestions.

sprocket