I use a dealer plate plastic cover mounted on the back of the plate. Its reasonably rigid and keeps the plate from bending and also provides a much less sharp edge around the plate. Typically pop rivet to the fender and then mount plate to the cover with standard Used to put them on frontwards as you would on a street bike but the mud gets between the cover and the plate and "obstructs the view of the numbers". Go see your local dealer and ask nicely for the clear solid plate cover then proceed to mount it on the back of the plate where no one can read it! My last one came from Apex Cycle but I also have a GP cycle one on my 300. Also use the cheep licence plate lights you can buy that are built into the plate screws. This gives me a licence plate light without too much bother and add no real complexity.