It is really hard to find a flow regulator compatible with Nitrogen in Europe. Because of that, is Argon just superior?
Or is Argon worse for the exit bag method?
Flow regulators that are combined with flow meters devices can all be used for Helium, Nitrogen, Air, Oxygen, Argon and CO2. However, each regulator + flow meter is calibrated specifically for a certain gas. You can use the regulator + flow meter for other gases if you use a conversion calculation. For example, if you use an Argon regulator for Nitrogen, you need to multiply the reading by 1.19
I think both Nitrogen and Argon are recommended by the PPH but since the air we breath is about 80% Nitrogen, its more natural to breath.