I read Hellboy in the oversized library editions only. I wait until each one is published, and I have not yet read anything else concerning the BPRD. It is one of the best books on the shelf, and I like reading it with bigger pages, because the art is gorgeous. These watercolors are similar if not the same to the art that is used as the covers for the library editions. They are centered on the books, printed on cardstock that is the size of a postcard.
I am a bit of a Mignola fanatic. A bit.