Without trying to sound too negative here - would it not be better to remain below levels where hypoxia is a factor, than to get hypoxia then "perk up" using Oxygen? Something about flying knowing that you are at high risk of hypoxia sends shivers down my spine...
If this reduces your range or similar then tough. I'm sure your employers would prefer you to arrive with the aircraft intact than for you to get hypoxic and prang it into the ground 20nm before the destination...