I have a number of balls drilled like this. For me, to get a Pin to PAP of 5 or 5/12, the pin will be left of my middle finger, this distance gets me very easy length.
Putting the pin under the fingers will make the ball change direction slower down lane. I have a Fury Pearl drilled like this, CG is in the positive/thumb quadrant with a low X hole. Still in box dullish, nice length, but a smooth, lazy arc on the back end. Works great on fresh Cheetah, used it on broken down Scorpion this summer, playing between 4th and 5th arrow, but tight around 3rd arrow down lane. Good hitting power, at least for me.
Same idea as pin on your grip line under the fingers, but just more length as the pin is farther from the PAP.
Your mileage may vary...
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Storm
Brunswick