Of course they are made for Airstreams. I contacted him to find out how big they were. They fit a 24" door opening. On my aluminum screen door the outside dimension is 20 1/4" the inside opening is 18 1/4".
Sooooo these won't work. I have been kind of kicking around a few ideas for a insert that would fit a Shasta door. I think if I found a good sized piece of thicker aluminum I could cut a piece to fit the door opening. The design may not be as intricate as the ones I'm showed but I think it could be kinda cool.
If you could have a screen door insert what would it look like???