But we are dealing with a resistive load. No inductance or capacitance.
A resistive load will not concern itself with phasing. So the 3 phase
thing is moot.

If we had a 3 phase device that has an ouput function, motor,
transformer or the like then we would be dealing with other things like
is the 3 phase Delta or WYE? And is the loading on the 3 phase,
phase-to-phase or phase to neutral/ground.
Bob AZ