first thing i'd do is strip all the vanes off a couple arrows and get them shooting on the same horizontal plane as a fletched one. adjust according to the unfletched one. it'll move more than the fletched one. then you'll have your nock height, or close. then i'd set centershot by doing some walk back stuff. zero in at 20 yards with your 20 pin until you're confident its correct. then go back to 30 and shoot at the same dot (near top of target) with your 20 pin a few times, and then from 40 with your 20 pin. if your arrows are going left from 30 and 40 then move your rest a little right, or vice versa and go back to zeroing in from 20 and start over. when you're done with that and shooting a vertical line then go back to 20 and shoot a horizontal stripe. if you're dead on it, cool. if not play with your tiller a little bit - take 1/8 turn out of your top limb and see if it gets better or worse. when you're done with that check that nock position again with bare shafts and fletched arrows. i don't put a lot of stock in bare shaft and fletched hitting the same spot, just on the same horizontal plane. the reason is sometimes mine do and sometimes they don't because a bare shaft is much more succeptable (sp?) to me making minor mistakes in my form and release. if its always off by more than 2" left or right you could have a spine issue, or a dirty release (i mean bad form)