I used flat white paint for my screen, after I wet sanded the previous paint on the wall. The strategy you might want to take is to paint the wall flat white, before you decide on the actual screen and the size. That way, you can find out what size picture works best for your size room. Could be, you'll be happy with just a painted wall, and won't even have to buy a screen. It's helpful to better understand the size of your projection, before actually buying a screen.
not sure I answered your question, but -- all the advice I ran into was to project against the wall before you make screen decisions. If you go with a pre-made screen -- know that certain type of projectors work better with the different screen offerings.
