Theo nailed it! With my sets, you just flip-over the comma. I don't make a lot of signs, but when I do I've never experienced a problem. Also, it ain't rocket science to make your own templates to drop-in. The homemade templates can be made from plexiglas. Drill the ends of the character needed and connect the holes with something like a dremel rotary tool. Cut the plexi to final size after you're done with making the character slot. Once you've made your own characters, it will "open up a whole new world".
OPG3 Tweak everything!