do any of the site (since Jazzo, our other source is off bathing) list the pitch of his famous roof?

The exact slope, I would say, is not really important. Mansart developed his famous roof because of the Housmann reforms in the late C19. Part of his regulations for new construction limited building height by number of stories (to ensure that his grand boulevards would be sunlit). The top floor was considered an attic and did not count against the limitations. To squeeze in an extra useable floor, Mansart created the steep roof, and his innovation was immediately picked up by others.