There is nothing wrong with adjusting the wing incidence if you are not pleased with the flight characteristics of the model.  Just shim up the back of the wing with a popcicle stick and see if you like the way it flies better.  Increase the number of popcicle sticks one at a time until it flies the way you want it to.  Its not going to hurt anything to try one popcicle stick at a time.</p>

I just adjusted the wing incidence on a Thunder Tiger Trainer by doing this with a piece of 1/8" lite ply I like the way the plane flies better... it no longer climbs like crazy with throttle increases.</p>