The worst case would be if you removed the only piece of Cobblestone that existed on the entire Planet, which considering how I plan on spontaneously generating “Block States”, might be a very common case actually. However I dont think that will matter a lot, because if you have looked at how Minecraft handles the setBlock Function, yeah that one is inefficient as fuck and will likely be much more laggy than my Octree thing.
After thinking about it, it could just be always 8 Nodes too, if that makes iteration for collision and storing the Nodes easier, since even if you happen to be in 1 Node, that Node could still be split in 8.