Forget about the weight and fly the plane. The wing area on these planes will allow you to 3d very well even at 20 pounds. As long as you have a powerfull engine like the DA or ZDZ or even the BME Your all gravy. The plane will fly and 3D with the Zenoa... But you will need a lot of space to recover.
Also dont take the CG thing so serious. The numbers are meant for a first flight type of thing, She will allow you to change up her CG quite a bit to fit your flying preferenc and style. This is one of the easiest giant scale planes to fly and will land like a feather when the fear wears off.