That's a great looking plane. Since you have no idea where CG is I will assume you are a beginner. If so put that plane in storage until you have LOTS of flying experience. It's a handful and will snap at the mere thought of it. Anyhow basically CG 's are commenly at about 30% of chord. To be safe don't have it any further back than that until it has been test flown by an experiences pilot.