FWIW... hydrogen particles are so small that they can penetrate metal. Containment is a very real issue, so make sure you get an actual "hydrogen rated" tank.I need to find a source for an 80 cf or smaller Hydrogen tank preferably from a place that will refill it also.
"Hydrogen, the second-tiniest of all atoms, can penetrate right into the crystal structure of a solid metal."
https://phys.org/news/2019-02-hydrogen-effects-metal.html
But you may already know that...