Pin placement from cg means very little actually.  Even Del Warren from Track says there is absolutely nothing wrong putting a pin that is 4 inches from the cg under the fingers.  When you are laying out the bowling ball, the two major placements are the pin and mass bias from the axis point.  If you draw a straight line from the bridge to your thumb and another one on your center line, that creates 4 quadrants on the bowling ball.  The quadrant that has the cg tells you what quadrant to place a weight hole if it needs one.  EXAMPLE:  You drill a ball with a 4 inch pin under the ring finger and you have an average to below average span (approx 4 1/4 inches and below), the cg is going to be somewhere near the thumb, meaning you will have a good amount of thumb weight in the ball.  This means that the cg is close to the thumb, your weight hole should be UNDERNEATH your center line or axis point.  Most people draw a line from the center of grip through the cg at around 4-5 inches away from center of grip and drill your balance hole in that area.  That is a good spot due to the fact that in order for your ball to flare over the weight hole, that ball has to flare a long way to clip it.  I am finding this to be a VERY popular drilling in my area (pin under ring finger with balance hole below center line for increase flare resulting in better midlane roll and overall hook.  I hope this gives you a better idea on this topic.
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Steven Vance
Atlanta (Buford), GA
Pro Shop Operator
Advanced Bowling Solutions

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