The reason I was wondering about the use of the downhaul is because I was told that is was used to open the top as as you sail into a gust.
Following the advice I obtained here has worked much better however. We do chache the setting while we sail along, but we deal with the gusts differently, as described, major settings (downhaul, rotation & boards) and minor/dynamic settings (Mainsheet, luffing & traveler).

We did go over last tuesday as we crashed while double trapping with the spin up. (It was great of course, and if you do crash you might as well do it fast). We did break our boom, got a replacement yesterday.

What troubled us a little was how quickly we went "turtle", that has never happened before sailing my Inter17. As we got our mast stuk in the mud approx. 30 cm, we needed some help to get back up again. Apart from the boom, no additional damage. We did find quite a lot of water in the hulls, I suppose that got in there through the airholes in the inspection hatched while upsite down.

Maybe a separate thread, but how does the guy steering the boat manages to get of the boat backwards? I think I might have been hanging around to long on the upper hull trying not to hit the boom or sail, and by doing so pushed the boat turtle. I could no however get off the other side, and slid down onto the boom.

Anyway, we had a great sail, and we are full on the learning curve in getting this I20 experience under control ;-). It is amazing how much fun it is even after sailing the I17 for the last 4years. (Don't get me wrong: I still sail and love the I17 as it gives me the freedom to sail whenever I feel like it, and i enjoy it immensely)

Take care! Martijn