I located several available books by Harold Hall besides the one you mentioned, "Milling a complete Course". Which other book by Harold Hall do you suggest?if you want to be a real hobbyist you could make your own parallels as a project on your mill. In the Workshop Practice Series 35 Milling a Complete Course Harold Hall describes a method to make acceptable parallels. I have made two sets.
Enjoy your machines.
Ray
As a side note for those looking for books here is a link I found for almost any books with really good prices and free shipping worldwide.