A balance hole affects the final hook and roll characteristics of the ball if put in the correct location, or it can have zero effect if put in a different location. It does matter very much where they are placed.

My question is that to make the ball "legal" will this hole have to be put in a certain spot or would the driller have options as to where to put it. We discussed beforehand the type of reaction I was looking for.

My question is that to make the ball "legal" will this hole have to be put in a certain spot or would the driller have options as to where to put it. We discussed beforehand the type of reaction I was looking for.

If its solely for making it static legal, typically a PSO will draw a line from center of grip through the CG to the VAL. Where that line intersects with the VAL will be the x-hole. That's the basic procedure for determining the x-hole for static legal. Yes, that does affect ball reaction characteristics. If you want to be more precise in fine tuning reaction with and x-hole, a PSO can place the x-hole closer or further from the thumb and he needs to account for finger, side, thumb weights before and after x-hole placement to still maintain static legal. If you are looking for that kind of expertise, then I would recommend educating yourself on the Gradient Balance Hole Location from Mo Pinel. After that, I would definitely go to a PSO that is familiar and experienced as well. Hope this helps.

wiki.bowlingchat.net/wiki/images/c/c6/GradientLine.pdf
wiki.bowlingchat.net/wiki/index.php?title=Gradient_Line_Balance_Hole