I need a projector screen for doing presentations and new/upgrades of software demonstrations in our work Learning Center. The projector in the room is an Optoma TX-762 and is ceiling mounted. The room configuration sits about 30-40 people and the size is 20' x 40'. The projector is set to display in the middle of the 40' wall with the people seated in the first row about 8' away and there are 3 rows deep. Currently they use a small 60" portable screen that people can't really see a good software demo on. I want to purchase the largest screen possible that will give viewers the best image for displaying software demos from a PC. I imagine it would have to be a motorized screen as something that large would probably be a PITA to raise and lower manually. (There are 3 whiteboards behind the screen that are also used sometimes without the projector.) Any ideas for a budget screen that could do the job?