At a bare minimum, you need a quarter scale. You can find your PAP with one as long as you know where your initial (release) track is. You can also use it to lay out the ball. There are lots of other interesting tools out there (armadillo, ball compass, etc) that make the job easier, but aren't essential.
Don
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"On-base percentage is great if you can score runs and do something with that on-base percentage. Clogging up the bases isn't that great to me. The problem we have to address more than anything is the home run problem."
~Dusty Baker being a total fool