I will be getting a Infocus X1 unit in for a few days. I'll have some recommendations after that time.
Initially, without seeing the unit, the Specs suggest a white screen will do just fine, as the Contrast Ratio (CR)is high enough for using white alone. then, your particular set-up may allow for a da-lite high power screen, which will work well with PJ's with High CR's.
For alternative mounting positions,a regular white screen will work well, or depending on what it turns out like,a grey screen may apply. I will try both. If a grey screen is chosen, a smaller image size will be the result, as lumens will be lost on grey screen. With a white screen, and the PJ in the video mode, the lower lumen count will probably dictate that he screen not be large than about100 inches diagonal, to maintain any sort of realistic light out put. too little output ends up resulting in an image that is perceived to be too flat and undimensional. Going with too big a screen can be fun at first, but it does result in an inferior image. Only having the PJ in hand to experiment with, will actually tell.
