I can fly me ARC 630 (4.3 projected) hybrid-foil in 24kts up to 40-45 kts. The highest winds I've ridden were 39kts. I use the smallest bar to prevent extremely quick turns of the kite and the speeds can get incredible. It definitely requires an extra mode of kite-attention, riding in winds this high, when you're so used to the large, light-wind kites moving slowly. However, by the middle of the session, I'm riding much more comfortably, and in control.
The ARC 630 absolutely rocks in high winds with incredible depower that will allow me to probably ride in 50 kts wind (controlled, but at the extreme range). The advantage lies in the rear attachment points. The further forward you move them, the more depower you get, and actually get faster turning, but since the ARC flies off front lines, the rears are slack so the turning can be easily adjusted by sheeting the bar out a bit....a great feature unlike inflatos. Also, the ARC's auto zenith tendency helps when you wipe out. Let the bar go and the kite rises to zenith and waits for you.
I tried the arc 630 out in strong very gusty winds and it was scarry as hell. It was my frist time trying an arc and I had a hard time figuring out how the depower worked. It seemed like the power and kite speed were inconsistant with what I was doing with the bar but it turned really fast all the time. Maybe the kite needed tuning and surely I could have used more practice.
I do not think the gusts were anywhere near 39 knots. V, you are a brave man.
My impression at the time was that the kite was not well-suited to gusty conditions.
The trick for me in high wind flying was Ocean Rodeo kites. Front line flyers allowed me to hold way more kite than surrounding riders. What these kites miss on low end they triple in top end. As well big tip of the day is that it allowed for glide like landings so big air lots of hang. small kites are no good for new tricks because you come down fast. These kites allowed for so much more time in the air because bigger kite with seat harness and wake bindings. Lit to the nines and not for bullshit brag but able to hold 16M in over 30 knots. Glide to new trick landings. ride hard die free.