I think the wall are just big enough and, I found the city kind of simple. Anyway this is my process sketch, adjustments are all in my head but i dont have the time to make them visual for others. Consider all of your thoughts tho.

chicken, i remember that when u say it. Reposted it to stop the comments based on ppl prejudging this because they think i dont know wt im talking about.

and YES dust filtered gasmask are mandatory ! both in my graffiti classes and for my own concern !