I am currently flying this plane and love it.  As far as cg I just used a 2 oz. brass spinner nut.  If like mine your landing gear pancakes on a not so lite landing you can get a beefier landing gear, which also helps.  I do STRONGLY suggest that when you get tired of paying top dollar for glow fuel that you think of switching over to a DLE 20 cc.  I LOVE this engine. All I have to do is move my batteries a little bit and it will balance perfectly.