I am currently assembling a guillow's F6F-3 hell cat, after pining down the wings, and taking a few measurements i attempted to calculate the total wing lift using a close match to the airfoil design as the CL <effiency of the wing>. Yes, the kits are a bit heavy and you do need to alter the wing design slightly to reduce takeoff speed. I achieved this by changing the wing twist, and shifting the airfoil axis up slightly. I think it will work well, but it will also create a little bit more drag. NOTE: The main cause of drag on a object is not the leading edge, take much more care on the wing tips, and back edges of all flight surfaces, if the air does not mix right at these points you will get alot of "vortices" little swirlies that will drag down the plane. This is the first RC plan i have attempted to build, I decided not too use any of the landing gear parts that came with the kit, and am going to fabricate fully retractable landing gear for it <gear needs a little bit of shock absorbtion, origional design is too ridged>. also i felt that the flight control surfaces if assembled by plans would be restricted in there free range of motion, so i'm changing that too. yes, i am adding a little bit of weight but i believe i can overcome that with the right prop/ engine set up. this thing is going to scream