Leonard,
I am flying a JR Models DiablotinXL with a ZDZ40RV engine. This plane is 87.5" wing span and length (long mother) and although I have not had it on the scale, I estimate it to weigh 11 lbs as well. This ARF also took me some time to assemble, but I double bevelled all tail surfaces and recovered. I have had the Diablotin muffler break on me and am right now in the process of soldering up a Crumscheib header and mounting a KS can. Why did you go with the more expensive and smaller 3WExtra and 3W24i engine? I will admit it looks like a great plane, but if the DiablotinXL is available cheaper, I would chose that plane. The DiablotinXL has double reflexed wing ribs and is just a dream to fly. As I am working on mine I am also moving radio gear around to get CG further back. CG is about .5-1" behind recommended without adding weight.
DKjens