What about plexiglass? You could drill holes and use zip ties to attach to the railing. It would be invisible too. They sell it at Home Depot or you could go to a glass store and they will cut it to the proper size. There is a home down the street from us that has a deck they did this to and it looks great. If I didn't know it was there you couldn't even tell.
__________________ “Never argue with a fool, onlookers may not be able to tell the difference.”  Mark Twain |