Thank you for asking for my help. I'll take that as a compliment.
Alas, although I have read several books on ball physics, my limited finances have prevented me from attending the IBPSIA school on drilling equipment. Therefore I'll leave the pin placement and mass bias location advice to a Pro Shop
However...you guessed it...I have input. Just not from the perspective of the science of ball drilling/physics.
I agree with you. Change equipment to keep delivery as consistent as possible. I encourage the bowlers I coach to use finger inserts and thumb slugs. This gives them the same 'feel', no matter what the ball coverstock.
A quick review of ball variables:
Coverstock (from controllable to reactive):
Each coverstock characterisitic can be varied by:
Sanding (smooth-rough) and Polished (lotsa different polishes)
Side note: sanding and polishing urethane has a different effect than sanding or polishing reactive/particle.
Ball reaction can be changed by drilling:
On-axis (least reactive to the coverstock) to leveraged (most reactive) and everywhere in between.
Although it puzzles me, there are times when plastic makes sense as the primary 'strike ball'. It seems that once a bowler purchases a plastic ball and calls it their 'spare ball', they feel as if they are violating a cardical rule by pulling it out of the bag on desert-like lane conditions.
I think I just wrote all of this and still didn't answer your question.