Boeing F4B-2, came in at 12 pounds complete. I used sub C 6 volt battery pack behind the fire wall, all controls as far forward as they would go. Required just over 3 pounds of lead in the cowl to CG correctly. So, it was now almost 16 pounds. I still have the plane, it did fly scale except it wouldn't loop without a dive. It is a slug and it's great trick is the stall turn, all it wants to do is fall out of the sky. Landing is really easy though. Take off and landing are really scale looking.
Any plane that had a radial engine was short coupled because of the engines weight so you will know before building it's going to be way tail heavy so you have to compensate during the build. I didn't!! I sent the plans to a friend and his came in at 12 pounds and is an outstanding plane in the air. Before the build I let him know the problems so he was able to think ahead.
How much lead?? As much as it takes. This plane is a 68 incher and you heard me groaning when I had to lift it. It's just a wall hanger these days unless I need something to fly at an IMAA event.