am planning on putting this projector in a 12x17 Fully enclosed HT room. My seating postions will all be 12' from the screen. I am trying to decide on either a 80inch screen or a 92inch screen. I can put the projector on a shelf in the back of the room where it will be 17' from the screen. At 17' what is the smallest image that I can make with this projector? If I cant get a 80inch image at 17', how much closer do I have to put the projector to get an 80 inch image? I can also ceiling mount it. I would like to put it as far back as possible from the screen while still being able to project an 80inch image.