Matonanjin, I read about this a few years ago on the Gibson site and one of their forums. Dave Hunter is the final inspector there and wrote this one time about setup for humbuckers on the Gibson factory line.
Hi I'm David the final inspector at Gibson Memphis. I can give you the factory spec info. on our setups. You will need a mechanics rule to do this properly.
To check neck relief: fret the low E at the first and 15th fret (not 12th) reach to the 7th fret and tap string. There should be a small space between string and fret - no thicker than a piece of paper. Do the same with the high E.
ACTION: fret low E at first fret and measure the distance from the bottom of the to the top of the 15th fret. It should be 5/64". Do the same with the high E, measurement should be 3/64". Now measure the string height at the nut; underside of the string to the top of the fret. Low E and A should measure 2/64", D and G =1.5/64" and B and high E = 1/64". If string height at nut is correct, recheck string height at 12th fret with strings open. Measurement for low and high E's should be the same as measurement taken at the 15th.
Pickups: Fret low E at 22nd fret and measure pickup height from underside of string to point on pickup closest to string. Bridge pickup should be 3/64" (I think the 3/64" is a typo, it should be 3/32") , neck pickup should be 4/32". Fret high E at 22nd fret, distance for both pickups should be 3/32".
Play test: Play every string at every fret checking for buzzes. Bend High E string 1 and 1/2 steps, beginning at the sixth fret and ending at 22nd, checking for "choking" and to make sure string stays in nut notch.
And this is interesting also: http://www.gibson.com/news-lifestyle/features/en-us/pickup-height.aspx
Besides, It not like your going to break it if you experiment with the pickup height. And as Ben said you can't adjust the pole pieces on the minihumbers anyway. I did see a 325 on Reverb yesterday that had the pups changed out. Hope it works for you.