How should I install a door that is not pre-hung and has a custom jamb?
I like B, because the most critical jamb is the hinge side.  Once its plumb, with shims behind the hinges, I rout the hinges in place with templates.

The other 2 jambs are "loose" until the door is hung.  Then, with a helper, the gap around the latch side is dialed in, starting at the latch.

The top jamb is done last and isn't as critical, structurally, as the other 2.