Yep, the real ones did the same. That's why the Camel had a pilot adjustable tailplane. Since you went to the trouble of removing the original, probably better to have just built a much lighter (laminated outline) tailplane, of the original section, and just set it at a more positive angle. That way you still alter the trim, and remove a bit of nose weight at the same time while retaining the scale section. Win-win situation. As the trim is speed sensitive, why not just use the straight and level speed as your normal cruise speed? 20 mph at 1/6 scale is 120 mph full size after all, and just about right for full speed. Even at 1/5 scale, it is still 100 mph full size, and just right for most Camels. That said, I do understand the extreme speed/trim sensitivity of these old things, something the new pilots of the accurate full size replicas are just finding out. You should see the amount of 'down' elevator held on, for example, the latest rotary powered Fokker EV/DVIII versions during 'S&L' flight at full power. So even flying with what appears to be a lot down trim on the elevator is still 'scale'. I really don't get the 'elevator must line up with the stabiliser or else something is wrong' thing at all. It simply means that you are exceeding the 'zero trim' speed of the aircraft. FWIW.
Evan, WB #12.