Hello Vlad,
I hate to contradict, but I have different data about incidence angles, or lateral dihedral as it used to be known. I can't explain the science behind it, but from actual experience, your model should have positive incidence in both upper and lower wings, and the tailplane as well. With a scale-type airfoil, you might try these angles for starters: Upper and lower wings set at +3 deg, tail(stab) set at +1 deg, engine set at 0 deg. If you fly the model fast, you may want to shim the stab to 1.5 deg, or possibly more, to prevent the model from balooning. I`ve messed around with these angles quite a lot, on different ww1 designs. I tried 0 deg once, and needed 4 deg engine downthrust to keep the nose down. Other input on this subject would be great, I'm learning that simply using the full size a/c angles don't always work the best.

John