Well, it's clear to me now that the height of idiocy is 7 feet. The challenge of working with a tall painting continues. I worked today on the painting while it was lying on its side across an easel. I had to think through the direction of my brushstrokes as they'd appear when the painting was upright. I also found myself unable to be sure what the result would look like until I got the painting upright again. I could, though, see a lot of areas where the paint needed work that were impossible to detect when it was standing.
So after working for a while, I flipped the painting back up. Not something easy at all and I don't think I'm going to do that more than once again in my tight space. Time to see how the painting dries and how it looks when I can get it actually flat against a taller wall (right now it's got bends where the canvases connect since the ceiling is too low).