We were taught in the altitude chamber during basic flight training to recognize the effects of hypoxia, the solution was to go to 100% o2 with the mask...in 10 years of flying, I never doubted my O2 supply or any of my life support equipment. Can't imagine what those T-45 squadrons morale is right now.
And, from what I can tell, the training is even better nowadays. After they take a class on hypoxia, they park the pilot in front of a PC based sim, in a small chair like any of use would have, with a control panel from their particular bird, stick, throttle, nothing much better than any home system. They wear their own mask & helmet. BUT, they plug their mask into a special machine they have, with tanks of various gasses. The operator can change the mixture, say O2 to N ratio, to simulate various conditions, altitudes, contaminates, OBOGS failures, and so on, with any timing they want. Even the breakage of a mid-air refueling hose, blasting fuel everywhere. Right after take-off, 2 hours into a flight, whatever. The pilot has to recognize what's happening, and take the appropriate action. Pulling the green handle, descending, whatever.
Most of the pilots are absolutely amazed to wake up breathing pure O2, and realize they passed out from hypoxia, without ever noticing a thing. Even pilots who've been through the Barometric chamber, like your-self. Those operators are sneaky, and really know their stuff. It also lets the other pilots see what the effects can be, and to recognize them in others, Helping them with checklists, talking them through procedures, taking over radio responsabilites, etc etc.
Really super good training. It's saved a lot of pilots, especially in planes getting old, and encountering more and more OBOGS failures, like the F/A-18, or T-45. Apparently not perfect though...
Take care!
Pat☺