Interesting reading, thanks! It seems to me the method ought to work, so I am not surprised by your experience.
The only thing I feel a bit uncertain about, not having tested it myself yet, is the practical aspect of two persons holding the same stick at the same time. Doesn't it get a bit crowded at times, with three hands on the same TX?!
Is the instructor holding the TX with the student standing on his right, so that the student can reach the right hand stick? I guess the instructor would want to handle the throttle in the beginning, so I presume that is the way it is done.
I will see if I can talk my wife into some flight instruction in RealFlight G2 a little later. Then I could test the method on her. (I am sure she would really appreciate that!

)
Krister