Welcome to the forum.
As for the "progression", i wouldn't say I've followed it at all because SSHE wasn't out when I started, and once I read and digested it then GSiH came out and I bought it for the NLHE content. I also picked up HEPFAP and the Split Pot and Stud books along the way, and now I'm studying Harrington I. So I'd say I've practiced accumulation of 2+2 books rather than progression.
The books recommended by Miller for each game are IIRC as logical as anything else. They're not all 2+2 books, but certainly most of them are. It's hard to deconstruct their recommendation into an unbiased opinion, though, because on one hand they sincerely believe their books to be the best, but then again that belief is well warranted, at least IMO.
You may find this useful:
http://poker.wikicities.com/wiki/Books -- we're working on sort of a reading list, hopefully in a logical order
Also the Books/Publications forum is a good resource, although as you note the search is dubious. Recent consensus is, you're better off using Google to search this site.