I don't work the industrial side of the street, but my general impression from NECA shows is that cable tray holding MC up through feeder sizes has taken off.
Greenlee has a whole series of specialty tools entirely directed at pulling in MC -- over pre-existing MC -- in industrially sited cable trays.
For the situation at hand, you might be well off buying even second hand MC from Salinger or its competition. You only need a trivial amount.
BTW, the big move has been to aluminum -- to include Bus Duct.
IIRC Westinghouse invented Bus Duct and put it on the market circa 1938. Eventually that division made its way to Cutler Hammer.
As popular as it is for industry, Bus Duct took off in the high rise sector. Tugging in big conductors vertically is brutal. Bus Duct is why going vertical has been so much more economic since WWII.
