Why not just use the thumb hole for balancing the ball, so put it where it normally would be and then he can set his hand on top of that spot like Belmo and Osku do.
Yeah, I think Belmo's thumb hole is more like a balance hole.
Still trying to process the info on page I-5. It seems that with only two finger holes, the ball can be oriented in either direction as long as the static weight is offset no more than one ounce in any direction. (Things will really be crazy if the static weight rule goes away.) The middle of the grip is between the finger holes. So if you put the CG in between the fingers, the pin could go anywhere.
Adding a third hole that is NOT covered by the hand could work as a balance hole. It seems that if the hole can be used as a thumb hole, it is considered such and the middle of the grip moves to the middle of the span.
Adding a forth hole limits the orientation to a conventional position. I guess. heh
Darn...I ordered a ball with a 3 to 4-inch pin. Anyway, better to stick with layouts that are proven. I'll let people who can afford to experiment figure out more flexitlbe layouts for two-handers.