In the 35% Giles manual, Tom has shown a way to balance a plane that is just too simple. I wish I had thought of it.

Just place a piece of 1 or 1-1/2' pipe under the fuselage and line it up with the wings, then find where the plane will balance on the pipe. It's just waaay too easy to do. Needless to say, a long piece of pipe would likely be the easiest way to line up with the wing, but it be a short one just as well.