MFortney,
I have a high track also, not as high as yours, but it used to be. I would also clip the thumb hole. But I pose to you this question, why do you wanna change you track?? That is not always the answer, people may post things that you can do as far as your release but I will not. I tried to lower my track and when I did I started spinning the ball(not a great thing for me), but as I progressed in the game it gradually lowered. How are your balls drilled up? If you are just clipping the thumb by a little, I would go with drills that have the pin no lower than an imaginary line from your ring finger to your PAP. That should help some.
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Roto Grip forever!!!! What else is there??