You'd be lucky to hit 900 lumens best case scenario, high lamp, short throw, iris open, dynamic mode- but this is worst contrast performance scenario as well (and obviously terrible color). You'd be starting with about 14ftL there if you did.
You put it in THX mode, keep high lamp, shortest throw, iris all the way open and you've got about 725 lumens which results in ~12ftL.
Best contrast mode with high lamp (iris closed, long throw) you'd have ~5ftL, and halfway (50% iris, mid-throw) you'd have about ~8ftL.
Add bulb aging and you're screwed no matter the scenario. This is all assuming Seymour's 1.2 gain spec is spot on- personally, I'd only account for 1.1 gain in your calculations, if any.
I'd say 11ft wide is about the largest size screen you want to go with the RS35 and little to no screen gain.
Throw a high gain screen in the mix, and 160" wide is certainly attainable. The problem there of course becomes speaker placement.