As soon as I got my physical copy of Carcosa, I did this. Another advantage to that book being small and thick rather than big-and-thin like most RPG books.
Publishers--is it possible to get things from the factory like this? Or at least do thumb indexes?
The illegible notes along the bottom edges are the local races keyed to the Carcosa races ("purple men= were rats", "red men = jackalmen" etc.) so I can convert the hexes as I read.
So far the hexes require remarkably little conversion to do a passable impression of Drownesia or Cobalt Reach. And there's lots of empty space for notes on each hex, so the dungeons and cities that make up the meat of the campaign can get stuck in anywhere...