Well, if your shooting 3 under, I notice 1/2" over center (top of the nock 1/2" notcenter of arrow)is a good starting place, and then when tuning, I usually have to move down 1/16" of an inch. I like to start off bare shaft or paper tuninga little high. When I say 1/2" over center, I am referencing the bottom of the shelf. thats on two martin bows I have that have even tiller at the fades. I heard that bows tillered 3 under will be tillered even if the pivot point is between the throat of your handle and shelf.