Hi Bruce,
The enclosed link above should give Wouter the information he needs for his calculations. FROM MY UNDERSTANDING, and I have been wrong before, various "in-the-know" sailmakers can design sails that are on "the edge" of class legal.

From the day I received my MX package, it appears that the numbers have dropped to the point that I owe time to a Hobie 20, am rated even with a Mystere 6.0 and have to come in on a Nacra 6.0 NA's castings. These are all 20 foot boats. The boat is not that fast.

Good luck with what you are trying to do.
Dave