So we found some adjustable screens at Lowe's online. I don't know how many different types of school bus windows there are out there but as far as my 2007 International goes these couldn't fit better if they were custom made. There is just enough squish in the weather stripping on the top and bottom to fit perfectly when the window is brought up to the first click and the thickness fits perfectly in the window channels. The best thing is that they are less than $8 a piece (we bought 10). We're pretty stoked! See the attached image and check out the Lowe's link
That's great, thanks for sharing! It's amazing how well those fit in your window. Not sure if they'll fit as perfectly in mine, but definitely worth a try for that price!