Just throwing out another idea.

In looking to satisfy the one design sailor and the AQ requirements. Maybe choose three boats. I would choose the F18, A-Cat and Hobie 16. Have three starts, one for each. Minimum 5 Qualify per class. The winner is the lowest score regardless of class. Everyone races their class, there is a contender for the Championship, and you do not have to worry about Portsmouth numbers.

Odd boats do not get to play. Different areas may choose different classes.

Is is totally fair, no, but it is something different.

Later,
Dan