Really good stuff..you see so many ruins where people just don't appreciate just how much mess and rubble buildings make when they collapse..and not just rubble but bits of glass (acetate sheet), wooden planking from balsa or lolly sticks, roof tiles (I know how much you like cutting individual ones). Like to see how you intend to finish the walls..that will really give them more of a date. I reckon some use of brick sheets bonded with pva then plastered around would give the desired effect. And maybe sprinkling some of your rubble mix atop the walls prior to the final plaster coat would make them look really ruined. Also like the idea of sections of buildings which have been re-inhabited and have been patched up with tarps/ packing crates and bits of pig iron.
Can't wait to see how these turn out.