Ok, I have been giving this a lot of thought. What is wrong with going with "Outside Box Rules". IE: having maximum specs and allowing boats with less than the max be in the class. The exception being boat length. This gives the developers more freedom.

I am sure there is a reason for the Nacra F20 to have an 11' beam instead of 12' beam. You must remember the extra beam width does no good unless you are using it.

If you set the maximum values according to the largest factory parameters that are out there now, it allows all to compete in the class. Over time the manufacturers can increase their specs or offer upgrade parts/packages. Could mean additional revenue stream for the manufacturers.

The only issue I see is minimum weight. You might want to put different minimum weights on different beam widths. Obviously the wider you go the heavier it will be. If we are using the Nacra F20 as a model for many of the parameters, you will need to add a little weight for the extra foot of beam so manufacturers don't try to trim the weight off critical areas meeting that weight.