Ah, interesting about the Kobo books. Blackmask was the old Munsey site. When he first started out he had everything in PDF.
Thanks for posting those!
I wonder if everyone has seen Mike Grost's informational site - probably, because it's been around a long time. For those who haven't, it goes into a lot of detail about these writers and others.
A Guide to Classic Mystery and Detection
http://mikegrost.com/classics.htm