Mike,
Shoot them at the current length for a while, cause you can always cut them later, remember you can make them shorter, but you can never make the longer!
Anyhow, after shooting for a while take a wooden sping type clothes pin, and clamp it to the arrow shaft, and draw the bow so the clothes pin hits the fron of the shelf, and measure from the side of the clothes pin that touches the shelf to the valley of the nock, and this is your draw length. This is a good way to check your draw length yourself with your own bow. Add one inch for broadhead clearence, and your good to go...
I'm willing to bet your draw length will be shorter than you think. Remember draw the bow to a comfortable position, and don't try to draw it to the next town!
Mike