Custom Bow Equipment (CBE) have sight tapes that you can be used for almost any bow speed. You purchase the sheet of tapes, sight your bow in at 20 yards and at 50 yards, get some really accurate readings, then match up these marks you have with there tapes and find the one that has the same distance from 20 to 50 yards as you have on your sighting in marks. It works extremely well for me as it does for alot of my friends. Good Luck. You can order them online at http://www.custombowequipment.com/