I finally got a chance to fly my P2Z in very little wind, perhaps 5mph or less. The uncontrollable yaw was much reduced so I think the lesson is that if you no yaw you want no wind. Still I get lots of shake and can't understand it:
https://www.youtube.com/watch?v=9u_ZlvlRYMw&feature=youtu.be
https://www.youtube.com/watch?v=9u_ZlvlRYMw&feature=youtu.be