Thanks Bowl Freak I assume you are right handed?
Now John P. Is that how it really came about, I think that is sort of what I had heard too!
Just to expand on what you said. For the 1/8(second easiest) or 0 middle finger hole(easiest), pushing down one side of the grip does not exist at all for 0, and barely exists for the 1/8, I think you will agree!
Now on the 5/8(hardest), yes one side will stick up the most and pushing down is harder, I believe we could agree on also, right? Of course a solution for that is triming one side of the bottom of the insert at an approximately 1/8" angle if it is bottoming and leading to compression of the rubber.
Just to digress to Bill Taylor's comments. 0 lateral pitch middle and 5/8 lateral pitch works for virtually all fingers.
Fascinating, and yet with inserts we now vary FAR from that! One would think that it would be because they with inserts now fit differently. Instead it seems to be just like you say, to assist the driller in insert application and longevity of the grip solution.
Hmmmmmm...which leads to a question. How does it affect hand position, and how does it affect ball roll. To some this may be the more important consideration, right?
Something to marinade on, I think!
I would love to hear from other old time drill gurus like Bull Red about this transition from "Bill Taylor" fitting for form pitches, and "Insert" pitches or fitting for Insert cosmetic and installation ease.
I apprecate your answers and hope to hear more! YOUR thoughts?
Sincerely,
Luckylefty