Per GP instruction manual:

CG is 5 1/4" (133mm) from the leading edge.

3D Control Throws
If setting up your Extra 330S 1.60 ARF with 3D throws, you should be able to switch to high or low rate throws during flight in case you find the 3D throws too extreme.

3D Rates
ELEVATOR: 2" [50mm] up 2" [50mm] down
RUDDER: 6" [150mm] right 6" [150mm] left
AILERONS: 1-1/2" [38mm] up 1-1/2" [38mm] down

Hope that yhelps