Very interesting thread.
I have read that in the days around when this was recorded that engineers spent time on getting the source to sound good.
Once that was achieved it was easy to record it.
Most of the big ones had very good rooms/gear with which to make that happen.
You probably know of recordings of this era that don't sound so good as measured in today's terms.
So I think they probably did not think too much about the recording process like we do today. As important as that is of course the recording was probably pretty much a standard operating procedure - once the source was agreeable.
It was business and they were cranking them out at a fast pace.
Probably why there is not a lot of detailed information out there.