Hal:Unfortunately there is no single publication with the type of information you are asking about. [It's on my "bucket list"].
The primary research on this subject was performed by Barbara Mueller in the 1960s and 1970s (yes, that's almost ancient history!), and was published by the US Stamp Society in
The Specialist as a 7 part series in 1972-73 (issues No 512 - 520). These articles are available on the USSS website:
http://www.usstamps.org/The Mueller articles do identify most of the Exchange Offices, but you should consider most of the details, notations used, and especially the number of items recorded is now out-of-date.
About 2000, several collectors (Al Kugel, Eliot Landau, and Nicholas Lombardi) began to develop a Census of the known covers with labels from the "minor" Exchange Offices, initially excluding New York, primarily because of the large number of covers known.
Lombardi was responsible for the Labels being listed in Scott Catalog ( a great boost to the hobby), but the dimensional information was developed by an unidentified third party, and I have never been able to obtain images of each of the specific sub-types of the New York labels from him.
The Scott Catalog valuations are nonsense for the most part as well.
This Census is published on-line at:
http://www.usstamps.org/committees/...study-group/and is updated
irregularly. The Census for San Francisco and Boston are maintained as two separate files as there is a larger number of known covers for these Exchange Offices than for many of the smaller and less active Exchange Offices.
This latter link points to the
Registered Mail Study Group page, but this group is inactive with no leader. I attempted a while back to stimulate interest in the subject with little success.
I have a private census of these covers from the New York Exchange Office, consisting of some 3000 documented covers (with images), and a file of cover images for probably another 3000 covers which I have not had time to process. I "harvest" cover images from
ebay, Delcampe, and all the major auction sites for future study. [Thanks to
Idhaber for adding his cover to my harvest.]
If you have general questions, continue on the SCF Board here, and I'll answer best I can without "writing the book" on-line. If you have specific questions or prefer to continue offline, contact me via the private message system.
Mike