I've voted but I acknowlege that different countries need different specs. I can see that Wouter needs the extra weight to build his metal frame so thats probably where he needs the class. Personally I would be embarrased to show people a 12ft modern cat that weighs 60kg and I wouldn't consider building one so what about having different classes of F12 with a handicap. I will refer to mine as a Light Weight F12 (this came to me the other day when I sold my light weight sharpie). Wouter could refer to his as the F12 Technical or whatever label suits.
regards