With all the help here and in PMs and email, and after talking with the shop again and they're confirmation that it does work, I researched converters more and bought this
AR-10 Rotary Phase Converer
Given where the buffer will be in shop floor plan, it makes more sense to put this converter in the compressor room (far away from the breaker box) and then an outlet joining an outlet in the adjacent room where the buffer will be.
I like that it's a US made product and their tech support staff were very helpful.