he can tell because my finger nails touch the back of the holes
Okay, try this - put your thumb in the ball and set your fingers across the holes - your hand should be flush against the ball, but COMFORTABLY (don't squish it). Now, can you insert your fingers into the ball. Look at it with common sense.
Drilling to fit your hand is a science - telling if it's right is NOT. Seriously - it's YOUR hand.
So, take a look - your fingers don't hinge 100% on that first knuckle, and even then they have to curl back toward your hand. It's about 1/4" that they come back . . . try it and see. This means you will have to stretch your hand to get your fingers in your ball and slide your thumb in - that's not good.
What will happen? Tendons will get stretched; you will have to grip the ball to have it stay on (which we all noticed - ever wonder how we knew that? LOL); and eventually your hand and your forearm and elbow will begin to hurt because the ball is not drilled correctly.
My advice, for what it's worth, find a driller who will actually look at your hand, measure your hand, and then drill the ball the way you want it drilled.