I also definitely concur with the point Buzzard Bait is making above about the effectiveness of an RC elevator rudder only airplane powered or unpowered for use as a trainer. Indeed they can be very useful in the training environment and seamless in transition to elevator and aileron or they can be horrible. Its all about design, that is the bottom line.
To this day I still actively teach Full House as well as Rudder/Elevator and heck even a bit of Controlline.
John