Hey guys, in case you aren't aware...
GUE Tech 1 teaches gas blending for our standard mixes, EAN 50, 32%, 30/30, 21/35, 18/45 etc., its really very simple. For O2 cleaning and handling, I'd recommend the Oxyhacker manual.
Chris
Edit: Oops.. sorry guys, I thought I was posting in the SoCal...