[wbassett]

I definitely advocate doing an initial setup and calibration on a unity gain white screen to establish a baseline.

In this case it may not be feasible since you have a pro painter doing the work. Unless he doesn't mind painting the wall with a white primer and then coming back in a few days to a week to finish it. In that case I'd probably go the safe route and say get an N9 shade of neutral OTS gray. You have light control so that's not a major issue, but if you decide to have some lights on now and then you'll benefit from the slight shade of gray. Also it's not such a dark shade that with total lights out you'll see any performance hit.

So the question obviously is... what paint? That depends on what your contractor uses. Find out what brand they use and then we can give you some recommendations and get you hooked up.