If you've moved everything you can move, and the engine is mounted as far forward as you can safely, then you pretty much have to add weight to the nose. The easiest way to add weight is with a "heavy hub", like the ones made by Higgly. Or you can glue/screw lead weight to the firewall. Chances are, you don't need much weight, and a couple of oz weight wont affect a .40 size trainer.