It appears I have the same condition with my Pitts. After addressing all the other concerns, My flight today was not good. Level flight at half throttle required 1/2" of down elevator trim! Inverted required even more. Roughly checking the angles indicates the bottom wing is negative in relation to the others. I'll have to get a meter to check the angle accurately.
Generally, when a bipe lower wing and stab are at zero to the thrust line, the upper wing is up to three degrees negative. I'll post results when completed.
Running Moki 2.10 with 5% Omega, K&B 1L plug, Bisson Muff, Hitec 475 servos in the wings and rudder, 545's with one reversed for the elevator. Some personal but no special mods. Dumped the OEM spinner in favor of a white 4" Top Flite Warhawk spinner to eliminate the horrific vibration. Easy lift-off and easy landing. More in-flight checks to come
Regards,
DrGO