I know, I'm causing trouble.
Not even if you tried to!
Addressed things which are indeed very related to this scope.
I like the descriptions of Transformers, which basically caught my eye - and led to this reply!
To the original poster:
Although the idea of using an oversized Common Grounded Conductor for several multiwire circuits is compliant to the NEC, it still just sounds odd to me!
It works, and should be safe - if installed properly; it's only a "different" method, very much "unthought of" by many of us here - including myself!
Regardless of which option you choose - be sure to have a "Balance" of Ungrounded Conductors which are derrived from Breakers on "Opposite Polarity Points" in the Panel.
Simply, if you can measure 220-240 VAC across two Breakers, use these two circuits for a single multiwire circuit. Step down 1 space from that multiwire for the next one.
BTW: Per the term "Opposite Polarity Points", I use that term because "Opposite Phases" really does not apply to a 1Ø 3W system.
Talk about starting trouble