If you use a CG formula to calculate it using 30% MAC. It works out to be 10 inches from the wing root leading edge, not the wings leading edge.The guys in Germany are using 10.5 inches. The book tells you 8.5 to 9 inches. I would go with 9 inches and then start moving it back to see how you like it. Better a little nose heavy then tail heavy to start with..