Mike:
I have gotten very eroneous cg reading from the great planes machine due to the fact that the arms are at an angle. I have also seen other posts of eroneous reading and do not trust in on larger planes. I measured my wing and the wing hold down bolt is 6 inches from the leading edge. Try putting your wings on and bolting them on with as large a gap as you can. Then wrap and tie a string on them and hang your plane from the ceiling. This will be far more acurate. You could also drill a small hole in the fuselage side at 5" and run a string all the way through the fuselage. The wing will cover the hole latter anyway.

Stupid question, but I assume that you do not have any fuel in the tank? Guys with much heavier gas engines are not having to put any batteries in the rear, let alone 2.

I quickly calculated that you are tring to offset a couple pounds off the nose with that much tail weight. Hmmmmmmmmmm Something is not right. Hopefully it is the great planes cg machine. I lost a plane because of this machine.

I took the metal arms off the plastic base. I then drilled holes is a 2x4 base at different widths. The arms are now straight vertical and I have not had any problems since.

Paul