Just by looking at the corn dance , and the wind in the camera , I was guessing 12 to 15. The graph you shared shows the winds were above 5 mph all flying day pretty much, with average speeds up to 10 mph . I do apologize by my saying there was a 2 to 7 mph error in wind speed above the documented speeds you shared , it's been 10 years since I have flown at Argonia. But by your Video alone, also by your additional mention of the M650 didn't kick like that, the wind must have been a factor. I know the additional weight in front of the CP wouldn't do that.