I don't own an F18 but here is my thought.
You need to do one big event a year. You can't do two or you will force people to choose. Especially if you did an East coast NA's and a West Coast Worlds. Then a lot of teams would choose the NA's that are closer to the East Coast and this would hurt participation in the Worlds.
A 3 day event prior to the Worlds would be a little silly. Most teams would not choose to race for 8 days and possibly hurt their boat just prior to Worlds.
I think counting the Worlds as the NA's is the best solution understanding nothing is perfect.
