The plane should be horizontal when the CG is set. Use a Robart incedence meter on one of the wings to determine what horizontal is. Of course, remove it when doing the balancing. If the wings do not use a symetrical airfoil or there is some incedence in the one you are using you will be off a couple of degrees, and therefore a little bit in the placement of the CG but you will be close enough for a successful first flight. You can readjust it then to your liking. Use something else other than the top wing as the balace point. It is too stable from there. Dan.