Nice looking model! Of course I'm prejudiced because I like yellow.
A simple adornment for a vertical tail is to just put a quarter inch wide black stripe outlining it, spaced about a quarter inch in from the actual edge of the fin. Makes it very visible when you're flying by and it goes with any color scheme. If you decide later to put something more on the fin, the center is still blank and waiting. Also easy to remove if you decide you don't like it.