What kind of window treatment(s) should I use? I don’t want to reduce light any more than I have to, and I don't want to put a film on the windows.

The handle in the middle, for the top window, juts out about a quarter of an inch into the room, so I don't think I can do interior-mount, unless I do two separate blinds or shades.

I don’t have air-conditioning so both windows are open most of the summer.