@garage sale GT - if you turn the nut in the other direction, you simply loosen it. The only way that doing this could work to apply pressure to increase tension in the saddle is if the nut fit behind the backside of the nosepiece.

Reassembling this way is trickier than initially appears though, even if the nut does fit behind the nosepiece.
This is because the bolt threads through the metal loop that is attached to the rails. So turning the bolt would thread it at an equal rate through the nut and the plate. So I would need to turn the nut while holding the bolt fixed with a screwdriver.