The set is catalogued on page 69 of my book, though I hadn't seen the Fitz before. It is a very tough issue to find. Appears to be a 1904 issue based on the record backs. They're not from any publication I know of. My SWAG is that they were issued in the West because of the Britt and Nelson cards. Those two were San Francisco-based in 1904.
ETA: coincidentally, I came across a George Dixon today:
