Harry
Thanks for the thread it's always nice to hear good things about Cat Sailing.
If a F16 Class Flag isn't available could I suggest adopting the Y-Yankee flag.
The Y Flag is made up of yellow and red stripes which is similar to the Spanish Flag. A Spanish explorer was the first European to discover The Chesapeake Bay in 1525. Also, The Chesapeake Bay was the venue for a Naval Battle where the French defeated the British Navy during the American Revolution in 1781. British Officers nick named American soldiers Yankee doodle dandy's due to their extravagant uniforms.
I hope you get where I'm coming from. Anyway, it was just a suggestion!! and I hope you have a great regatta.