I am going to take a stab at this; drilling will only change a balls designed reaction to a certain degree. If a ball is designed to be a controlled ball, even the max layout will not change that much, of course the amount of revs to speed ratio, of the bowler, will also have an affect on it. There will be others who will answer from more technical experience, but I believ that I am in the proverbial "ball park".
Dave
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If You Are Not the Lead SAW, All You Get is SAWdust!!