For me, there is no strain at all. Brightness is at normal levels. Sitting that close actually approximates what I imagine sitting in a real pit would look like, and the immersion is great. That said, I think you'll be more than happy with a 42 inch (even with just a single display).
I often run with just the HUD display, which works well and gives me approximately 10 more FPS. I just wish ED would provide a 'bathtub' view so that you could actually see the wings and tail when looking in that direction.