RE: 35% Sukhoi Wing Problem
Just be aware of the way sheeted foam wings work.
The foam doesn't actually do anything except give the wing shape and hold things in place. The strength comes from the sheeting being in tension (pulled along the grain) and the foam just gives it a shape.
Sp pay attention to the integrity of the sheeting especially around the end of the wing tube which is where most of the force is concentrated.
TF