How do you handle a classic double barrel with a tang safety in the field, shotgun or rifle?

I've always carried rifles and shotguns of various action types with an empty chamber, but never used a double in the field. Range work is easy: empty until ready at firing station.

So how do you handle a double with internal hammers safely, beyond the basic four rules? Say a Browning or Beretta 686. Walkabout with empty chambers, action closed? Broken in the crook of your arm? Chambers loaded and safety on?