I too learned on the 56. Great bird. Have flown both, and they both fly good. Either would be a good trainer. The tail surfaces on the 56 are built up and have an airfoil shape. Can't remember now how the III was cause I didn't build it, just test flew it for the guy and taught him on it. Seems they were not build up, but I could be mistaken here.

On my 56, I knocked the tail off once and put the tail on from an RCM 40 and it was flat. Still flew good.