STINSON RECORDS: A LOOK AT THE LABEL FROM ITS FOUNDING IN 1939
(Matthew Barton is with the Library of Congress.)

Thomas: Didn't see your question before now, much belated:

SLP-93 = 1974 - From the copyright on the center labels but with Stinson, who knows. It's companion to the book.

SLPH-93 = 1977 - From the same source. Both use the same cover art (SLP-93) but only this one mentions "Stereo" if I recall correctly. I think it might just be Stinson's first proper stereo release.

With few exceptions, the red vinyl was limited to the later "Collector's Series" reissues. They started in New York just before the move to the West Coast.

I still haven't figured out who did the mastering and pressing on them; an arrow pierced heart (Cupid style) badge and "delta" prefix matrix numbers. Afaik, it's not Hancock per the video.

But if Barton is right about the other stuff, no reason to doubt him, the family split started well before they left New York.