My suggestion:
F18 for men
F16 for women (or F18 with smaller sail set?)

One year before olympics, have trials from each manufacturer to select which boat will be the Olympic boat for ONLY the next olympic. The manufacturer has to supply the boats for the event.

(alternative, something like a OD Tornado for men, F18 for women).

This would provide a great junior -> olympic development plan for all countries (something like H16 -> F16 -> F18 -> OD20?), which is a HUGE part of the politics (you have to give the governing bodies a way of developing juniors.

By eliminating choosing one specific manufacturer 4 years before the event you allow the class to develop boats for three years, all manufacturers, helping the class. Then, by choosing one for the year up to the Olympics you give Olympic sailors the chance to buy that one and train for the year leading up to it.

Just my thoughts, but lets not forget, you NEED to have a junior through olympic training / development system in place. (Lasers, Laser Radials, Laser 4.7s, Bytes, Optimists for example, or 470, 420, or even 49er, 29er, 420...)

My 2 cents