I am almost done with my Super Stunt 60. All that's left is to put an engine in there. I did some mod like putting the elevator servo at the tail, used 3" wide elevator piece, and reversed (up-side-down) the engine mount to raise the engine to accommodate a larger prop. I tried the Enya 1.55 4 stroke I have on its nose, and it balances about right. But I really don't want to put this large engine on there. I was thinking more like a Surpass II 91. I want to do mostly harrier and quad flap stuff, not necessarily the vertical 3D. But it will end up being tail heavy if I put a 91. I am sure this plane is stable even when it's moderately tail heavy. So for those of you who have flow, what is the best CG setting? Instruction says 6" behind LE. I am wondering if 7" or 8" would make it harrier better?

I want to use either 15x4W or 16x4W prop. Yes, a 16" prop will fit and still have 1" clearance with my setup. What would be the recommended powerplant?