Hi can anyone help with aerodynamic questions?

I built a 3d plane using the root airfoil from the sig somthin' extra (constant cord) It requires alot of up elevator to fly any speed and lots of down when inverted. I balanced the plane on the the original spar location at first, then moved the cg back thinking it was nose heavy but no luck. Then moved it forward and still no luck. The stab area is about 25% of the wing surface area but it also has a shorter moment arm than the SSE.
It has a 51" span weighs 84oz with 739 sq in of wing area and a 52 two stroke.

Any help is appreciated.