Those are nice pictures, but belived me it's only balsa ribs that you see there and it wont hold very long, you should have a complet wing spar or an other tube going from one side to the other. An other factor that you have to remember is that fiberglass will get weak with the heat from the sun or other source. So no more strength from the fiber!
Since you can't open that wing box because you will break all the balsa ribs, you might try to shoot some insulating stirefome like the one in the spray can to glue and stik everything all together.

Also the spec that they are showing are wrong, the final weight will be around + /- 16 pnds.
That's what i had with a Zenoah 26ei.
By the way I had plenty of power for a scale flight.

The CG location is not right to.
I had to moved everething foward of the firewall.
My 2 batteries pack + 200 gms of lead steating on the engine + a heavy prop nut.
That is a pound right there. If you dont do that you will have a premature take off because of a to much foward CG
The only picture that I can give you is the next one, toke after the crash.
If you look the other picture, it's on the last takeoff so you can see the attitude of the plane.
Good luck and don't hesitate to ask me other questions