We had a similar discussion on this a while back.
It seems that some pilots manage the reversed controls GA/Flex without any problems, and others like me just can't do it.
I did a couple of circuits with an instructor in (on) a flexwing, and enjoyed the view and the shear practicality of the machine. But fly it I could not! Even with my utmost concentration the aircraft would progressively diverge, and every correction would be too much or in the wrong sense. I guess I might get it after much time, but it would always be like riding a bike with crossed hands.
My fear is that in some sudden emergency near the ground ingrained and instinctive reaction would produce a wrong control input. Sudden engine failure in a left hand climbing turn after t/off for instance. My instant unthinking reaction would be to push foward and to the right. Someone trained on a flexwing might pull back and to the left, which would be fatal if flying a GA aeroplane.
Just my pennyworth... perhaps instructors should spring surprises on pilots who have made the conversion, to ensure their instinctive reactions are appropriate to the aircraft type.