Basically asking BCtriguy1 but opening it out to everyone else here.

I'm hanging some pre-hung doors in my basement, so far I have done 4. 3 turned out great 4th, as good as I could, the walls are out of plane.

Final door is a interior french double door (with top ball catchers). How do I do this one? Currently the top is plumb and un-nailed, do I nail that in then plumb both sides? Or do I leave the top un-nailed and plumb/nail one side, hang the doors and check the reveal other un-nailed side then nail the top/other side in?

Basically I don't want to fuck this one up. If it matters, its on plank vinyl flooring which I already installed so the frame is sitting on the floor.