Saweeeet! I'm goin' Thanks for the tip!
I don't know the price these days but Princess Auto also has/had 7" round stop/turn/tail that I used to replace the boxy things on my Triple E Surfside
. This size covered two of the 4 mounting - screw holes in the fiberglass as well as the main hole for the wiring. Look pretty good and are quite bright. As I remember they were $24 per light