[{HVY-E}Jinxx]

You'd just have to tie the O2 on/off to the alt when the game engine puts on the mask.

I'm not sure about this. What altitude & planes does the mask on/off kick in. Maybe works for jets, but I've never seen this feature occur in a prop plane, and I know beaufighter pilots used to use O2 when they flew over the Owen Stanley Ranges from Port Moresby to Buna in New Guinea.

From what I've seen, it's at about 10k ft or so and works for all planes. Go below that alt and the mask automatically comes off.
You can go to external and watch it.

S!