Spandex Screen for my Epson 5025UB? - How dark can I go?

Hello,

I'm "upgrading" from a JVC RS10 to an Epson 5025 UB Projector. I have a batcave with very dark flat painted walls, ceiling, and carpet. I have a 112" painted screen with N9 Scorpion. This painted wall has served me well for the JVC RS10, but it's just 'ok' for rejecting ambient light. The JVC was perfect on this screen with the lights off, but didn't have much horsepower in lumens for viewing with the lights on.

I'm thinking with the Epson 5025UB and it's considerable increase in available brightness, I could try and use a darker screen material, maybe just for use when the lights are on. So, perhaps a 'removable' screen of some sort, while keeping my N9 Scorpion painted wall available for when the lights off.

So, maybe spandex is something I could try? How dark of a shade of spandex could I use with my 2000 lumen 5025UB from 12 feet projecting a 112" image? I know there are several modes, and the lower cinema/THX modes are preferable, but I'm referring to upping the brightness to living room mode perhaps on a very dark screen with the lights on a little bit. Most of our viewing is with the lights on just a touch?

Is silver the way to go? How would this projector do on say black spandex if I used Living Room mode?

Also, does spandex show sparkles? I'm *very* sensitive to excessive sparkling.

PS, Acoustics are not an issue as this spandex would go right over the painted wall if I did it.

Thanks!