all i know about sub arc is its flat position welding and they use some type of sand as flux, other than that i have no idea

"Have you considered making a home made roto phase to run 3 phase equipment off of single phase." i have no idea but its worth looking into, this 220 volt equipiment is not what im used to using. All the welders we use at powerplants are 480 3 phase. I guess i could y 2 220volt buzz boxes together so i could run 300 amps off of 220 current as another option.