Hi,

You can usually achieve the CofG by moving the batteries. If this isn't sufficient is it possible to move the motor to the rear on its' mounts? Adding weight is the last resort. BTW are you checking the CofG with the tank empty?

If you have to add weight add it as far to the rear as possible as a "little goes a long way" given you have most of the fuse to act as a lever. A few lead shot in epoxy or a cut down stick on wheel balance weight are simple solutions if this is required. A more "elegant" solution is to cut a small hatch at the rear to hide the weight. Just make certain the weight is well secured.

Cheers,

Colin