I originally started making all the walls with 1×2 gray plates (it is still that way on the front surfaces) but then I started to run out of 1×1 light gray and dark gray round plates. I used profile bricks and 1×2 light gray bricks in the pattern on the sides to conserve plates. By the end I had five or six round gray plates left … I probably used 1000 of each!
Your question about the wall depth is insightful. Not only would the wall be unstable but you’d be able to see through the cracks between the round plates. There is a layer of 1x6x5 light yellow panels, (and some black bricks,) behind all the 1×1 plates. This worked nicely to give the appearance of a soft yellow light through many of the windows.
