no one else has jumped in so I will try to help.
I have some poster view material that is just like window perf but has no adheasive. This lets you print as normal and then hang on the inside of a window. You would need to find a way to tack the corners or I have seen some hang like a banner. The ones that are not tacked to the window tend to curl on the edges a bit. By using the wiindow perf look, you still see through from the inside and not notice the graphic as much as you would with a mesh banner material due to it's backside not being black.
Clear focus is one who makes it and also have the adheasive dots to mount this material.