Would this work?
So buy 6-30R convert to L6-30R, use that to connect into the power supply above, than just connect the 4 rigs all into that power supply?
What do you mean by solid/neutral for the breaker?
I would just check that the circuit is wired with proper wire size and that your service grounding is good.
The PDU says the cord is a L6-30P but the connector is to L6-30R does that matter or will still work?
About connecting the rigs to the PDU, would they connect into a C13 or does it require another connector? I was planning on using Eve Energy plug:
https://www.elgato.com/en/eve/eve-energy
For each rig there would be 1 Eve Energy plug, and the Eve Energy plug would then have to be connected to the PDU I would assume.