Here's the up to date overview for the Circus Maximus:
Work has been a bit slow since I moved, but the new place has a more generous area for my hobby work and I'm back to work on this project.
I'm putting a double wall along the outside edge, and I should be able to set it up with some nice Roman-style arches along the decorative side.
Closeup detail shows the small brick tiles in use for floor panels inside the double wall. That's a detail should be visible through the decorative arches.