Hi Wout
Thought it may be helpfull to provide a link to Phil,s excellent boat const. oriented web site
http://www.geocities.com/phillbrander/

different related topic
--good effort on the rating system concepts and proposal,--it seems they all --all types of rating systems and design class rules ,inc Formula Class are all continually works in progress ,--constantly developing and refining over time and changes ,though much the same in intent through yacht racing history .-

Hope boat mfg will eventually get behind a Formula 20 category cat with common accepted basic specifications to go with the F-14 -F-16 F-18 ---f-20? concept in some form , perhaps based on the Tornado specs, which were the original B Class as defined ,-the T developed for selection trials in the B Class as Olympic class catamaran way back .
C