In my planned theater, the front wall will be approx. 16.5' wide by 8' tall. If I do a 140" wide screen, the height would be either ~5' (2.35:1) or 6.5' (1.78:1), either of which the room could accommodate. I can mask the 1.78:1 screen to achieve the same size 2.35:1 screen.
So ... I love 2:35 and most of my viewing will be in this aspect ratio, so is there any reason to buy a screen with this AR, or is the above thoughts RE: Masking correct and I should go with the 1.78:1 screen (and mask)? Remainder of front wall will likely be covered with black GOM.
The only way I'd do a massive 16:9 screen with masks would be if I was to a CIH + IMAX setup. Given there is only about 3 titles, not worth it IMO. 3D could benefit, but if 2D Scope is most of what you watch, then optimize the system for that.