I cant answer that question without knowing your entire setup and even then it woud be an educated guess to get you close.
Your best bet would be to have someone mark your arrow (CAREFULLY) while at full draw. If you will be hunting , your arrow should extend 1/2" - 1" past your rest at full draw (make sure your broadhead clears your riser at full draw). If you wont be hunting , you can cut your arrows to extend a 1/2" past your rest at full draw and you'll be good to go.

"Nocked,cocked & ready to rock"