"The system has only a drawback:
it works only on boats fitted with high masts (unirigged) and high aspect spinnaker (short footed)."
Strange comments. Looking at the photo`s the spinnaker looks more like it is short-luffed rather than short-footed. Perhaps the luff only looks short relative to the mast length (which looks rather long !) I`m surprised the hoist height isn`t a bit higher & the kite isn`t more high-aspect than it is, something looks out of balance with the design.Perhaps it`s just that VERY long stick. This is not negative criticism, just my personal observations which are not based on professional boat design, so don`t quote me or get anal about my comments. Overall it looks great, just the proportions trouble me a bit. I`ll get over it as soon as one sails past me.
In my experience it will be faster in light winds & become more difficult to sail as the wind picks up. At least it has 2 trapezes, finally I know the intended target market (2 up). So can you sail it solo, and how will that affect it`s rating ? According to ISAF the lesser weight will make it rate faster than the sloop version, since there is no jib to get rid of. I`d like to see a solo one outperform the sloop in more than 15 knots. It will take a special sailor !

Cheers
Steve