Actually, this just came to me but I could use aluminum channel on the top and the bottom of the screens. The bottom channel would be screwed to the wooden base. The top channel would not be attached to anything but I would use a dremmel to carve a three notches in it, each one like what you see on a barrel bolt lock. These notches would match up to three screws attached to the underside of the top rail of the stand.
Eg:
I would set the bottom of the screen in the bottom channel, then set the top channel on the top of the screen and swing the screen into place, matching op the notches to the screws. Once in place, I would just push the channel to the side and that would lock it in place on the screws. To take the screen off, just push the channel the other direction and swing it off the screws and out of the frame, and lift it out of the bottom channel.
Does that make sense?
- Chad