I use a gas arm on my single tier brewstand. The gas flows through a 2" x 2" SST tube to flexible gas lines that connect to the burners.
I recommend steel gas piping for your main supply line then you can step down to flexible gas tubing from there. You need to leak check all of your connections with snoop prior to lighting the burners. Install independent shut off valves for each burner. Gas plumbing is a safety concern and should be installed with care. If you are not familiar with it, I recommend hiring a licensed plumber for consultation and/or installation.
Do you have any photos of your setup you could post?