I can't see these being bright enough, especially if you're on a course in the city that has any light pollution. Makes me wonder if there's a glow powder on the market now that is appreciably brighter and more durable. We talked with a couple local coaters about using it on another project and they said it wasn't worth doing if it was going to be left outside 24/7 because what glow it did have would diminish quickly, and the sunlight would deteriorate it to the point of looking crappy and not working much at all after a couple years or less. Maybe there's a better one available now?