I used to run press-brake, all of my blanks came from either a turret punch or the lasers. We used O2, N2, "Mix" and compressed air depending on the metal being cut. My experience with the machines consisted of off-load and slapping another sheet on as needed.
The lasers were in a very large are, the gas bottles were huge I do remember that. They eventually went to a N2 bulk tank due to the volume of work that required it.
By contrast my shop is part of my living room and a second bedroom in a converted apartment. Running a volume of gas constantly is basically out of the question, even with the window open (as mentioned above.)
If I decided to go with this it would probably be as I described previously, manually inject C02 at critical points in the cycle. If I go that route I won't need a big tank and there would be a considerably lesser risk of ending up on the news. "Tonight's top story -- look what this idiot did."