You'd be better off using plastic boxes than going thru all that bullshit. Metal boxes are used in concrete and metal buildings where metal conduit is joined to each box and the wiring and boxes are all exposed, That is what this code is referring to. I don't see any conduit being used at all and his boxes are exposed and none of them are joined with metal conduit so none of it is truly code.
But you knew that already because your an electritian, I only went to college for Electronics engineering.
You are giving piss poor, illegal advice. Having worked with engineers for 30 years, I'll take the electricians. Plastic boxes are fine if you are concerned about inadvertent grounding on installation. If you want a safe system long-term, metal wins hands down. Future ground faults will then trip the breaker rather than set up a long, slow burner that takes your house to the ground. That's chief among the reasons that industrial installations are in metal.
Edit: you were posting while I was typing. Glad to see you came around.