Guess I can throw in the myth and soldiery drop rates for treasure maps. I didn't get any triple tome rewards from the small amount I did, but I assume they still happen.

Leather - No tomes, same as before.
Goatskin - 3 Myth
Toadskin - 5 Myth
Boarskin - 7 Myth
Peisteskin - 7 Myth, or occasionally 3 Soldiery

I am assuming Boarskin can also drop Soldiery once in a while, but I only did one, so I don't know for sure yet.