If you're building from the kit, I'd make two changes... Add fixed flaps like a Flite Streak. It increases the area and gives the wing a more finished look. It makes a noticable difference in the air. Also I'd slow the control response down a bit. Using the outside hole in the bellcrank can make the plane twitchy, using the inside hole makes it more smooth. If you don't like the slow controls you can always change the pushrod location at the control horn later. The kit fuselage is already long enough as is, I can't see any reason to change it.
If you were building from scratch, I'd toss all the lite ply. I'd also use full ribs in every location instead of the alternating full/half ribs. The plywood adds weight and doesn't hold up to crash damage as well as an all wood wing with full ribs.