I would start off by moving the rudder servo to the tail. The look to the nose to see what weight can be removed. Any excessive length screws? What spinner and prop are being used? Is the ABS plastic cowl being used and would a fiberglass unit be lighter? Is there a way to make a hatch in the aft fuse to mount the battery farther back? If you post a detailed picture of the engine install with and without the cowl we may have more ideas to lighten the nose.