As to the original question, many old free flight designs did use lifting tail with the CG farther back than what RC designs normally fly with. There were also some early RC designs that used lifting tails, but one of the problems with the approach was that sometimes when the airplane increased it's speed in a dive or steep turn, it could not recover. Flat sections, symmetrical sections on the tail did not have this problem and took over. Most RC design has been monkey see, monkey do.