My next question is the plane seems to be nose heavy, even though the center of gravity is perfectly to specifications. Any ideas on that? I have to add a lot of trim to the elevator to keep it flying even, or else it will start to go down.
Usually the CG is given as a range i.e. 60mm-75mm from say the leading edge of the wing. Try moving it back
a LITTLE at a time, an overly tail heavy plane is a crash waiting to happen. The best way to move the CG is to reposition the radio components and or battery. If that is not possible a small amount of modeling clay might do the trick