RE: Dual rackmountable power supply?

I don't think you can place these on the pointy side
of conditioned power. They require utility, IIRC,
which means you also need to add in some UPS for the front
side to make it work right since utility will tend to take
'switch hits' during peak as the utility moves load around.

WRT to the flapping power circuit, blind guess, ask your
colo provider to measure the load at your breaker and if
it's fine then swap the strip and chords (twistlock or not)
back to the first JB.