Mary F104 is a class much like the days when you had Prinde 16's and Hobie 16's...

Nacra 5.2's and Hobie 18's.

Prindle 19's and Nacra 5.8's and Supercat 19's.

The boats were level rated in US Portsmouth and state of the art in their day.

Your mileage might vary as to how even you beleieve the boats actually are.... leading to the old "horses for courses debate".

Level rated races were never popular in the US as sailors felt the pressure to support their one design class schedule and not a level racing schedule. I would imagine that the only way it works is if the French YC's and Sailing authorities only support F104 and don't allow a local majority of boats to split off and race one design by not hosting OD races.