The sponsored competition shooter I referred to earlier put the dual laser bow tuner on 5 bows, and 4 of the 5 was dead nuts with the lasers, there was one that was a little bit off. So what he can do is nock an arrow, make a pencil mark on the arrow at lets say 20 inches from end of nock, set lasers on the mark and lock the wing nut down, pull the collars tight and lock them down, take a sharpie and mark the outside of the collars on the jig so that you can always set your arrow to that point for that bow.