ProjectorCentral had a good calculator. If you can find out the gain, then you can figure (given you projector), and throw distance whether things will work. I've got a DaSnap, 106" HCCV (1.1 gain), that gave me a good range of ftlamberts for my situation, and will do even better with my new projector. BTW, Da-lite was kind enough not only to send me the blue-print of the snap location, but ... a bag of studs (I built my own woodframe, since I didn't know how long before I moved out of my apt. and didn't want to commit to an expensive setup). I've been recommending them to friends ever since. Did I mention they gave me the bag of studs, and blueprint free ?! Don't count on that courtesy, but I'm sure if you are a DIY guy, they'll accomodate you at a reasonable price. BTW, I picked up the screen from bhphotovideo.com. I'd check their prices, before I decided how much I'd pay for a used screen. I was surprised how reasonable the price was, and of course ... no compromise, I got to pick the exact size, composition, and gain I wanted (using advice from the dalite site). At bhphoto, look under AVPresentations \\ DaLite \\ Video/HDTV Format Replacement Surfaces .... it'll give you an idea of the pricing, but use the dalite site to decide on the surface, then give them a call, and get the price for a specific size ... they have a much wider variety than the listings, and you'll likely be surprised how cheap ... they treated me well, and the dropship came directly from dalite. Enough plugging ... just want to give something back to a couple companies that did well for me. BTW, if you do get one of the dasnap items, it'll come folded up, with nice ugly creases in it.
Once I got things installed, it stretched the folds out in maybe 10 days, and ... it's looked beautiful, for the last 7 years, or so. Yes ... sadly, still hanging out in the same apartment, looking at houses. Any day now, though