HEY MORE POWER
I too have a CG sukhoi. since your scratch building, I'm in the middle of converting mine to gas putting on a bme 44.
I'm also changing the wing set up. putting the finishing touches to a plugin set up. made an aluminum spar to fit exactly in between the spars, don't know why you couldn't use ply, I just wanted aluminum. made interlocking light ply that fit into the inside of the fuse locking into all the overhanging lips that will attach the wings,using the wing saddle to mantain incidence.
don,t know exact wing area yet,but I'm sure it will be more than enough, span will be at 78".
hoping to finish by this weekend.
mine before weighed exactly 10lbs. With a glow and heavy mount. I don't think I'll gain more than a pound, if that much.