Over the years I've had 5 Ultra Sticks, two 40 size and three 60 size. All of them were nose heavy. It's just the plane I guess. With the 60s, I put the elev and rudder servos in the fuse sides as far back as possible and cut a hatch about 1/2 way to the tail for the battery. Those two mods really helped to balance the plane. They only required a little weight in the tail after that. Try to add weight only as a last resort.
Paul