Official time is 'at least 3 minutes'
Follow that and you cant go wrong. But in general, airbags are quite safe to work on. In over 12 years, ive only ever set one car off, and that was because of a faulty ecu. Depending what im doing, i dont always disconnect battery.
As said, for the wheel, leave the nut on a few threads. And dont be scared to damage anything, wrassle like a mad man