As you can see in the above image that I have started adding color to the image. I have worked across the middle ( I am right handed so I work left to right and top to bottom). At this point, I will spend several hour straightening any lines and correcting any wrong angles (perspective, projection). I now have enough of the image colored that I can also make any color correction to my palette.
With this work I am going to stay with the warm colors and contrast with some cool blocks of color distributed throughout the work to give some balance.
I do not work fast and I really wonder about my sanity for even starting this. I spent over 340 hours on "Earth 1946" and it was a smaller work than this. This one seems to be going faster and so far I am pleased with it.