whats up!!! first i know there is a big thread of this plane, but i dont wanna search all the tread, it could take me hours

I'm having some problems balancing the Aeroworks Edge 60/90!!
The cg that i am using is 4 inches from the leading Edge. The plane is very sensitive to balance. if i put three 1/4ounces weights in the tail, the plane will go backwards, but if i touch the spinner then the plane will go forward... if i add more weights the pattern is the same. It never stay in an horizontal line (perfect balance)
What do i need to do? more weights or not?
i am using a ys91!!!!
thanks a lot guys,
Alex