Before you go tinkering with the up/down thrust, are you absolutely sure that both ailerons are adjusted to be perfectly parallel with the horizontal stab? If the aileron rigging is misadjusted, it will cause the elevator trim to be misadjusted, which could cause the problem you're describing.

The OMP Edge V3 is an excellent flying plane when setup 0-0-0. I've never seen one yet that needed any thrustline adjustments other than some prefer a small amount of right thrust.