Ok, It seems common knowledge that an arrow leaving the bow's dead center is desireable. Other than papertuning or watching for prong wear, is there an easy way to get it right the first time when setting a bow up initially?

What about the center shot finder that attaches to you limb bolts and has a lined gauge that you settle on top of you arrow then adjust center shot until it lines up in the middle? It seems like one could replicate this tool at home with a couple allen wrenches and a rubber band....