OK, Major,
I just now spotted your 6:01pm post. I plugged the numbers into the geistware CG application. It uses the formulas that've been tried and true for years. Saves us the effort to do the math.

It shows the model should be safely stable with a CG from 3" to 4.37". That would be with a static margin of 20% to a static margin of 10%. I usually set a CG at a 15% static margin for my model's maiden flights and they all have flown great. I almost always wind up moving the CG back a bit but haven't ever wanted it farther back than the 10% static margin location.

The 15% that geistware computes would be a CG that's 3.75" back from the LE of the wing at the root.

Typing this has taken longer than it did to plug your numbers into the geistware app.

That app is at http://www.geistware.com/rcmodeling/cg_super_calc.htm