What PSI is the natural gas in your building to start with? The studio I was working with in San Diego had a commercial variance to get 4-5 PSI to the building, and the feed line for the rooms were two inches. My memory if fuzzy, it has been years, but I think the feed line for the room with 6 minors was 1", while the PM2D room (also 6) fed off the main 2" pipe. I would want confirmation from others who have done this more recently, but that is what I remember