This door frame is done, with only a couple of very minor glitches. Fits pretty well, though I need to rebuild the hinges…at $75 each, not really excited at the prospect of new ones.
The door hinges are held in place by screws, normally, but they are fairly well known for giving up after awhile. I am using machine screws in slightly oversized holes and these homemade nut-plates (made using rivnuts and a piece of aluminum). Though my mortices are too tight to allow any vertical adjustment, this will give me the ability to adjust them in/out, and be a more secure connection over time.
I’ll trim them to fit within the post space, and mount them using a 1/16″ shank “washer screw” through a 1/4″ hole in the top center of the plate. This will keep them from falling but allow 3/16″ movement in any direction to allow for hinge differences, sag, wood rot, evil spirits, etc.