dlenart...I don't think he was asking about Pin to PAP distances, i.e. how strong to drill the pin.
ktallen...If I understand your question you are asking about starting Pin distances at it relates to the CG of an undrilled ball...correct? If so, a 3" Pin is usually an all purpose pin distance provided the top weight of the ball is around 3oz's or so. This usually allows for almost any drilling to be put into a ball (pin up, pin down, etc.).
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-Chris: DJ's Pro Shop : Auburn, MA