SPYDER, I think you have the answer on the pitch but also think you have not fixed the left turn using right thrust.

If it takes full or near full aileron to make it fly straight there must be an alignment problem! Check that the wings and horizontal stab. are in line, the vertical stab must be in line with the center line of plane, etc. I have had many planes that had no right thrust and all flew fine. It sounds to me as though the builder was a little sloppy.