There is no CG per say. We go by hang angle.....Hang the aircraft by the rotor axle....it should have a nose down attitude. If you follow center line of the aircraft, that line is your horizon. Once you hang the aircraft by the rotor axle.....your horizon line changes as the nose tips down. compare the center line to a leveled line behind it....that is your hang angle.

PS: You could have emailed me.....