I have never made a center shot self bow but the rule I was taught buy one of the most exsperienced bowyers I know was to be safe ,the handle should be twice as thick as narrow Down to 3/4 " = 3/4" x 1 1/2" if going more narrow increase the thickness , I know guys have made off set handles bringing the arrow closer to center & still keeping the dimensions the same , maybe others could answer better !