Artvin is right, you should measure where your draw is before you start hacking on arrows. But another idea if you don't have someone around put a loose fitting clothespin on the shaft and draw to anchor. Then measure from the throat of the knock to clothespin. I've also seen guys spray the shaft with some anti perspirant deodorant. It put a white pilm on the shaft, then as you draw the arrow, it wipes off, and you measure up to where it's wiped off. I also wouldn't use your fist measurement bcause that one will probably be a little longer, when you are consciously drawing the bow. Just be real ohonest with yourself and draw it as you normally would.