I’m building a G.P. U-CAN-DO 60, 7 channel Futaba radio, FS-91 Surpass 4-stroke Engine with Pump Unit. I read a few building/review articles, they were installing Sato 100s. Has anyone built this with a O.S. 91? How does the CG work out with the O.S. engine? How did you cut the cowl to fit the muffler? I read a few comments on beefing up the gear mount, is this necessary, and if so, what did you do to beef it up? A few people used washers to angle the engine from the fire wall, what did you do? The directions don’t suggest angling the engine, does it really make a difference? The only modification I plan to do is replace the control horns and rods, I’m using 2-56 carbon rods, and Dubro heavy duty control horns. Any tips or suggestions are appreciated, thanks.