More food for thought.
Just something i was told in the later 70's by a good friend's oldest sister.
4 parts in ZoSo - Z is Page - the 2 o's are bass and drummer - S is singer.
The Z is leading and supporting the other 3 on a pedestal.
That's why the bar is connecting through the oSo - so that they are all linked and supporting together.
She told it as in that it was true ...
doesn't make it right now or then - but it sounded authentic to me at the time.
fwiw