Pinbuster - Good concept except that it's pin and mass bias placement on balls with a marked mass bias (asymmetrical balls) that matter more than cg placement.
Even on symmetrical balls (no marked mass bias) the pin to PAP distance is more critical, though the cg placement does have more effect that on an asymmetrical balls
And if the ball is poured correctly the pin will ALWAYS be 6 3/4 inches from pin to mass bias.
A longer pin to CG distance on a ball will give you slightly more flare potential, plus if the pin is long enough that you do have to put the cg below your grip midline you may need a balance hole to make the ball legal depending of course on the begining top weight.
Adding an extra balance hole depending on where you drill it in relation to your PAP can/will add different amopunts of flare to the ball making it flare more or less and flare sooner or later. These are really more fine tuning tweaks. Cover stock matters the most.
You have more flexibility to tweak the ball reaction with balls that are longer pin outs and higher top weights. Just depends on if you want super max out of a ball or something else for ball reaction.
It is possible to have a farther pin out (over 3" pin) and not need an extra balance hole if the top weight is low to start with.
The guys to really ask that know far more than I do are Constantine, T-God, King of the Mill. Those guys have forgotten more than i will ever know.
--------------------
Zman
You haven't seen real LOFT until you've seen me bowl