Thanks for the help! I have a ZDZ 50 w/Bisson pitts, servos in the tail, 1800 mah sub-c nicad pack on firewall for ignition, 2-2700 mah nimh 6-volt packs placed between the bulkhead in front of the wing tube and bulkhead behind the firewall, with the fuel tank over the wing tube. With this setup, it is going to take around 13oz placed on the firewall to balance at 5 3/4 from the LE of wing at the fuselage (3 3/16 at tips).The only other mod I made was to epoxy the horizontal stablizers in place,but this did not take much epoxy. This seems like a lot of weight to me to get the aircraft balanced, has anyone else with a similar setup had to add this much weight to get it balanced?