OK I have this same Hanger 9 Extra 330L with a new ZDZ 80 single that I just flew for the first time last sunday. The engine has plenty of power even though I did not use much of it because I am still in breakin. As far as balancing goes. I moved to a singe JR 8611 for the rudder on pull-pull. Also have 8611 on all other surfaces. I used Fromeco Lion packs, two 2400's for the plane and one for the ignition. I placed the reciever batteries under the wingtube and the fuel tank directly on top of the wing tube. The ignition battery and regulator as well as the throttle and choke servo's are in the motor box. At this point I moved the rudder servo around in the fuse to find the place where the plane balanced. This ended up being about 1 inch behing the rearward set of anti-rotation pins. Anyway the plane balanced perfectly and is about 24 lbs and flies great. Good luck with yours.
ps. the ZDZ is the only way to go. much lighter and much more power.