Well, the more I think about this, the more I'm inclined to try to fit the light without removing material - mount the top end flush to the fender, get a couple of spacers for the bottom bolts to securely anchor the lower end, and then fill in the gaps more or less water-tight with something ... black rubber I can trim to fit, or perhaps some closed cell foam (I have some leftover black pipe insulation which might fit the bill). As long as it's black, I'm pretty sure it will disappear, as is will be almost completely hidden behind the license plate and my turn signals (if my mounting idea for
them works)...
Anyone have any suggestions about what I might try? How do you shape a thin rubber slab into a wedge?