RE: Old C.G. location
do what is the easiest - -all of these early types were simply free flight designs with some trim control -- the Radart - and Rudder bug - whatever your design.
Power (engine)should be kept low as these models again were setup to work in a fairly limited speed range .
So far--no one has introduced a Chinese Arf of the Rudderbug so minor deviations will likely go unnoticed -by the current crop of flyers -----