Kevin, I sometimes run with the nmca o/c guys and I do have a permanant # for nmca. I always just copy my permanent # in the spot on milans tec card Never had a problem. As far as size I think mine are 4" on the side windows and 2" on the front and back . Hope this helps answer your question. Also I might recommend. With lexan If your really talented I'd get the numbers so I could install from the inside of the windows, makes cleaning a ton easier.