The CG is 105mm (4.13in) behind the leading edge. The covering they use is Ultracote. I have a Thundertiger 91 on mine with no additional weight needed (balanced perfectly). I had several hard landings with the stock tailwheel no problems so far. I also fly off a grass field and fixed gear is a MUST. Took me about 1 hour for the fixed gear conversion, well worth it. Good Luck! You will love this plane.....