The buffer thing sounds like a good idea. When I set target surplus that's exactly what I'm trying to do. So automating that would be great. We'll see how that version of handcarts will turn out, but I think that between that and fixing structure inventories (no more farms with 70+ wheat waiting for pickup!), things should go a lot better.
The district part sounds like it should be related to merging settlements. Like if a settlement is merged into another and doesn't have separate districts already, it automatically becomes a district.