[OSM-dev] Tiles at home - meta-info for tilesets not individual tiles?

[OJW]

Is someone willing to modify tiles at home client so that each upload contains 
*only* tiles in one tileset?

If so, we could store upload information just for the z-12.

Unfortunately, that would mean that we need to search and delete any tiles in 
that area which weren't uploaded, otherwise an existing tile which you didn't 
overwrite would be tagged with your username. 

Maybe this needs to have the "force render of all 1376 images" turned on in 
the client, so that the first step of checking an upload is to see that it 
has every image expected.

Will this cause all sorts of confusion when uploads are dropped because a 
blank z-17 image is missing?