The hinges are heavy duty commercial hinges from McMaster Carr, and what's cool is that the bolt pattern matches perfectly with the fire door! and the screws fit perfectly as well! WOOO! love industry standards!
The hinge side of the door frame is 6x2 routed out to accept the hinges.
Then with the help of my wife Cathy, we muscled that bad boy into place with a 1/4" gap on either side. That gap will be stuffed with some felt then caulked with some SilentSeal before the trim goes up.