Re: the Goldberg Bucker CG, it would take me a looooonnnng time to dig out the plans, and today is 113 in Phoenix, with my shop not too far behind. However.....I remember making a balance beam from a popsicle stick, which attached to the bottom of the front and rear aluminum wing struts, and I had a notch in it about 3/4" ahead of the rear strut bolt. One on each side of the fuselage, stick your fingers on the notch, and there she was, per the plans. Good place to start, and you could move it back a little bit if you think that is too nose heavy.

Why not just balance it off the top wing? I got bit by that procedure many years ago, and I have a theory that the further you are above the mid-fuselage CG, the more you get a pendulum effect, with any out of balance condition dampened. Engineers may argue with this concept and if so, they are probably right, but I will continue to wallow in my happy ignorance if so :-)

Clair