Ok, maybe I wasn't clear.Then consider how you will watch 16:9 content on that screen.
I will never, ever, watch 16:9 content, I will just let the projector project a 16:9 image, at all times, overscanning my screen.
But I will mask when watching movies (2.40:1 movies is all I watch), so the 16:9 calculation will fit my 2.40:1 needs.
I chose a 2.40:1 physical screen because content being narrower, 2.35:1, 2.20:1 etc, could be masked down to 2.40:1, still filling my screen.
I have absolutely zero needs of using the motorized lens memory, I just zoom once and leave it be.
I will use lens memory for masking ON/OFF only, to see bluray menus etc.
Well..It depends on multiple variables, it depends on how you are doing masking, whether or not you will be using the Zoom method, how much lens shift you are using for 16:9 images before the lens memory switch, and what exact screen and room dimensions may constrain your setup.
19.6' throw, 118" 2.40:1 screen (124" 16:9 in width) makes for a 108" width in both cases.
Epson 6050UB, JVC RS540/X790R/X7900.
2' screen bottom to floor, 2' screen top to ceiling.
Lens center will be 78" from floor, shelf mounted.
The final screen height of my 2.40:1 screen will be 45.3".
I think I have enough lens shift capabilities in the vertical axis on both projectors, and I don't think the 19' 6" throw is any issue.