You can't adjust the incidence on that plane. And 1/2 degrre would not account for your problem.

I still think the elevators are twisted.

Let me ask you this; if the elevators did not have counterbalances would you even know there was a problem?

I mean what difference does it make if you are carrying a little up or down elevator if it flies ok? I may have a set of non-counterbalanced elevators/stabs, what color is your plane?

TF