You might visit Eastman's website and download the 34 page tuning guide on there. There are some real good drawings of what to do, and how to get there. It's kind of a flow chart: you need to have arrows that are spined correctly to the actual pull weight of your bow. Also need to know the draw length and tip weight of the arrow to zero in on the correct spine rating. Bow must be set up right in terms of clearance issues, center shot, cams, etc. Paper tuning will get you close. Then you must shoot groups with each type of head and move the arrow rest and possibly nocking point to get the two groups to coincide. Also, I am finding that certain combinations of broadheads and correctly spined arrows just fly better in certain bows - and are easier to tune to shoot together.