I built my own screen as well. I used a recipe for paint that I found on the AVS forum and painted a 4'X 8' sheet of plastic wall panel. We had a very challenging room (lots of windows and daylight) but the little projector (optoma H31) and this screen performed well. The paint recipe should be easy to find it included a Behr metallic paint.

M22's, VP150, QS4's, HK 630, HSU VTF3-MKII