There's a chart on the How-To section that can give you some info (a starting point). Like Kille says, you'll have to adjust for draw length and how center shot the bow is, and how heavy your tips are, and even how long your arrows are if, for example, your draw length is short and your arrows are long. What it comes down to is you need to look a chart to get a feel for what might work, then shoot a bunch of different arrows so see what really works. Sounds like a pain, but it's not so bad. It is shooting, after all!! Oh, and you can shoot off the shelf or stick on a rest. It's totally up to you.