I have a Modeltech Extra 300 that I've been flying for about a month.

It has a .40LA which seems slightly underpowered...

Does anybody know the recommended right or left thrust angles?

In vertical upright, the plane pulls left slightly. In axial rolls, the plane changes course left. In checking the current thrust angle using an incidence meter, it has +2.0 right thrust.

To get this plane to repond purely, should I increase the right thrust more - or should I be looking somewhere else?