RE: This DNU has "GOT TO GO"
Dave, a free flight guru taught me how to see if a plane will fly straight, or not. Hold the wing out at arms' length, with the rear of the wing facing you and sight down the trailing edge, looking for a twist, dip, or any indication that the set up is crooked. It doesn't take a trained eye or any talent, just a good hard look at it. The incidence meter is nice to have, but not needed. with the whole plane blocked up level on the table, you should be able to go around and compare measurements off the table as a reference. compare full deflection throws and accurate centering, [since you are using 2 aileron servos make sure the linkage geometry is identical]. If the plane is balanced and straight, it should practically fly itself and go where it's pointed. Also check the sturdyness of your control setup with the control surface at full deflection, you shouldn't be able to press against the flap [within reason] and move it much at all.