My “other boat” is a Flying Fifteen, and within their class they have an excellent system for open meetings / championships whereby the fleet races on scratch but also has additional awards within three separate sub-classes, based on boat age as determined by sail number.
Admittedly there is a distinction here compared to Wayfarers in that the FF was originally defined with broad tolerances, and a fair amount of development took place to exploit these in the 70’s and 80’s, thus earlier boats are clearly slower in open water. This is maybe not the case with W’s, where well sorted early wooden boats can be fully competitive.
Perhaps a different system would be to assume that everyone starts in the “bronze” class and moves up to “silver” at the end of the season in which they win a bronze award, and likewise from silver to gold, with perhaps a nominated list of known “gold” sailors being produced initially by mutual agreement.
Regarding measurement, I have to say I agree with kgough. My W is a rather beat up MK1 GRP which had been used for cruising, possibly for its entire previous life. I’ve now got it seaworthy and securely buoyant, and whilst all the work I’ve done on it is (to the best of my knowledge) within class, I reckon getting boat and sails measured would take up several days of time, involve several hundred miles of travelling and a fair amount of expense, given that I live a long way from the nearest measurer, up here in Cumbria.
So I sail it in club races which are pretty informal, but wouldn’t take it to an open meeting for this very reason, despite the fact that it is broadly within class and totally uncompetitive!