Bill Taylor's theory maintains that a certian degree (in verticle pitches (forward/reverse)) in the thumb hole is required to produce a free armswing and a clean consistant release. These pitches are based on the span length and the further your hand goes around the ball the more toward the reverse you need to go. Of course this is a starting point but should be exteremly close.
You can not determine the proper pitch until you have the proper span (or relatively close). Many additional factors have to be taken into account, such as thumb length, mositure, fexlibility ...etc.
Pitches are not a mystical or magical solution based on others results. Your span and pitches are completely individual just as you height, weight, color of your hair.
Find a reputable well endorsed pro shop operator, even if that means you have to drive 100's of miles. A proper fit is crutial to your development. Dont keep spending 100's of dollars on bowling balls without investing in the key that will make the most of the money you are investing.
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