I think it is hard to miss a time block, but 6pm should be good for most. A 5 minute pit break at 6pm is about how my body works.
Well if anyone forgets their Hawaiian shirt, you can buy your exclusive Gary Con Hawaiian shirt from the souvenir counter. We had custom fabric made with D20s and GC logo on a Hawaiian print. They aren't cheap but they look good!
Always go for retinal shock. I've a big believer in ugly, hawaiian shirts. Also, I'm a fan a very well done hawaiian shirts.