I don't have the Super Stearman, I have the PT17 Stearman and the balance point is listed at 15-20 mm from leading edge of bottom wing also. Thats where I balanced mine. I balanced it inverted between the 15 and 20 mm marks. It did take a few clicks of down trim to get level flight (not 5mm worth of down), but it flies great and flies inverted with very little down elevator applied. I would say it is probably at the aft edge of the cg range. It tracks straight and level and doesn't appear to fly like it is tail heavy. I would say the 4" on Kyosho's web site would be if you are balancing from the top wing. I didn't have to add any lead to balance with a Saito 56 in the nose. Hope this helps.fossil