RE: Which plane would an instructor fear the most?
I taught my grand son-in-law how to fly with a Ultra Stick 40 with a buddy box 4 channel system and the rates were rather quick. Needless to say he did not solo in three flights but he did learn - eventually solo'd and then flew several different kinds of planes on his on. It was what I had available at the time.
He's very proud to be his own man when it comes to flying models. There was no transition to low wing or tail dragger nor wind. He had essentially already been there. Not long after he solo'd he took a trip 750 miles away to the western U.P. to visit his folks and he and his dad went flying. He showed his dad how it was done.