My First OverHead Projector

I have been playing with the idea of finally adding an overhead projector to my dedicated music listening room. The room is 17.5 w x 26 L x 9 h. I have two sets of speakers in the room, (1)Magnepan 3.6's which are approx six feet into the room from the short wall and four feet from the side wall, (2) Klipschorns which sit in the corners of the same short wall.

I could hang a screen on the short wall and have about six feet of viewing space between the 3.6's. Or, if I run the projector I can easily slide the Maggies to the side and open-up the entire space (which I do often when playing the KHorns).

Question is, what projector should I consider? I would consider buying something used to get started. Also, what is a good screen option?