Where do you buy 200mm fans? Can't seem to find any

Also, looking at the panel where the PSU mounts, the screw holes aren't quite right PSUs don't screw in the four corners but 2 corners, one slightly off center from the corner, and then one off to the side. I have no idea who's bright idea that was, but I thought I'd mention it so you don't produce the case and find out 2 of the 4 screw holes for the PSU don't line up