The cobblestones might take a lot of effort, but your result is definitely worth it. The individual cobblestones look like, well, individual cobblestones.
It's like the armor modelers who use the individual track links that have all the pieces a 1:1 track link has, and assemble them. A lot of work, but in the end, it looks like a track link assembly.
For the amount of imagination you have in planning your diorama, it's worth it, this is turning into a photographic representation of the ruin.
Those cobblestones remind me of a company called Hansa Systems, who made scale building materials-individual cobbles, bricks, roof tiles, etc. I've never tried their product, but it's the same kind of detail.
Ah! I still have their link:
https://www.hansasystemsusa.com/
Looking forward to your next update, RE!