I've tried nickles, dimes, rulers......found that ears work the best. Usually start with the bridge and adjust up until the bass strings start to compress in a bad way and then back off until they don't. Balance out the bass and treb sides to taste. Match the neck pickup to the bridge and balance the neck pu to taste. The fine tune the middle position for max sparkle by using small adjustments on the neck pu. Done.
this is what works for me. I've spent years looking for some magic measurement and have come to the conclusion that pretty much everything factors in, amp, player, guitar, pickups, strings, picks....everything. best thing to do is spend an evening with a screwdriver and try em high, low, and everywhere in between. I don't get the ruler out until I'm done adjusting and that's just to document what I ended up with.
Its all about the ears.
Gavin Allred