I read that Bruce Bohannon breathed 100% oxy for over an hour prior
to his 40K+ RV flight, and know that it is standard practice to
turn the oxy on before takeoff of wave flights at Minden (where
25k+ wave is common in winter).

Bruce said he pre-breathes to purge nitrogen. I understand
Fossett and his NZ pal are also big oxy users. I'm interested in
what his altitude record attempts will look like after he is
done with speed records. I wonder at what altitude a pressure suit
is a good idea...

I've had serious hypoxia after several hours at 11K, and bought
oxygen after that flight. Gliding I seldom get that high since
my gliderport is at 780 ft, but if I was near the sierras
flying thermal or wave, I'd surely use oxygen frequently.