I don't think anyone addressed that question about three crew in the nine.
TAA had three for a very short time when the kerfuffle about flight engineers was on, while AnsettANA blokes went on strike if my memory serves.
I was young then and nowhere old enough to be in great big planes, but I remember being told by one of the cramped blokes who reckoned three was too many.
That was in the days when they rotated to 22 degrees ANU and couldn't see over the nose.