Hi I'm new here, and was hoping you're advice would guide me in the decision of this screen. Basically I need to purchase a projector screen for an NEC LCD 2100 (VT470) lumens projector which will be mounted on the ceiling. Its for a hall that is 80 feet long and 33 feet long. So its a fairly long hall. The conditions arent all that super bright, but not very dim, however sometimes we may have some bright lights on the stage where the screen will go. I'm looking at a 100" screen as thats the biggest that will fit the hall design, and been offered at a good price a glass beaded screen (gain >2.2) and a matte white screen (gain >1.1). I've been told that glass beaded screens have bright spots, and are retro-reflective, which means they have a very small viewing angle, plus the projector is mounting from the roof. But they look very tempting. Should I get a glass beaded, or a matte white screen? ALL HELP IS GREATLY APPRECIATED!!