I got a used Heat Blast drilled with the pin above and in between the fingers with the cg kicked out a couple of inches. It also had a weight hole down by the thumb. The weight hole gave me a little more flare, now the ball is nice and smooth with good continuation on a medium/light shot. I would like to duplicate that same reaction on a stronger ball for more oil. A step up from the Blast. I plan on using the same drill. Any suggestions. Oh, and could you limit it to symetric bowlingball? thanks.