Dave,
At last count there are about 2 dozen Tigers racing in California as one design with no need to join NAF18. I expect that number to increase between now and the Worlds. Not sure about how many other F18's there are in SoCal. I have heard of at least one NACRA. F18 fleet racing in SoCal will be a hard nut to crack unless other non-Tiger F18's start showing up.
Dan,
I consider the Spring Fever Regatta as a regional event not local.
John Bauldry
Hobie Tiger 1317
Commodore, Hobie Fleet 276
Detroit, MI