Here is the thing. The longer you go with the pin, the more you are storing energy. More stored energy = more aggressive backend reaction. If you want to soften up the backend, drill the pin closer to your PAP such as a 3 x 5. Putting the pin closer to your axis gets the ball rolling quicker which releases energy earlier, and therefore softens up the backend or making it "archy". A 6 x 4 type drilling with alot of hand as you put it, I think is going to create too much length and flip especially on clean backends.
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Steven Vance
Former Pro Shop Operator
If anyone out there is worried about the scores being too high, try duckpin!!