You should be fine at almost any angle...standing, sitting... what have you. I think 160-180 degrees you might have an issue from the sides. I have the 120" XY PET Crystal and have known to lay down watching a game or two on the couch. ;-)Am investigating UST system with a motorized ALR screen but require screen to be placed 1-2 feet higher on wall than normal since I must view from horizontal position (ie laying down) since I am disabled. I am concerned that an ALR screen will not provide the best picture since optimal viewing angle seems to assume eyes are at same height as screen. Screen diagonal between 100 and 120 inches. Looking a projector such as Optoma P1.
Need the ALR screen since blocking all light not possible in living room. Motorized since fixed screen (which I could tilt!) not aesthetically acceptable to spouse.
Can anyone with a UST/ALR setup comment on how quality varies with vertical viewing angle - hard to find specs from manufacturers and would not fully trust them anyway. It's hard for me to leave the house so any feedback appreciated. Long-throw projector would likely better address this concern but not practical for most of locations where we can place a large screen.