The CF tube is only 3mm. The wings are 2mm but with the bipe design, its very stiff. The tail is 3mm. The X2 flys fine, its my big wing standard tail Gym-Blu with the same CF tube that I'm having trouble with.
Yes, draw up some plans.
I think a lot could be gained by setting the two wings at a proper angle and a proper camber foil. I just used the LAR method. If I do another one, I would make the wings even bigger. I kept them small because I was worried about the strength of the 2mm depron. The desgin is plenty stiff so could handle larger wings. If you don't want to mess with the adjustable incedence, so far I found about 3 deg. to be the best for in the gym. At 0 deg. it flew fast and flat, maybe better for outdoor. At 6 deg. it wanted to lock into a harrier all the time.
Oh, and by the way, the plane probably flys better than it looks in the vids. I have only been flying for a year and that was my second time in a gym. Walls and hoops can be very intimidating!