The way it is currently assembled (which is how it was received), tightening the bolt (while holding the nut with a screwdriver so it does not rotate) will pull the nose of the saddle back towards the rails, instead of pushing it forward from the rails.

There is no obvious way to re-assemble the parts such that the tension bolt would push the nose of the saddle forward relative to the rails. Although there is a fair chance I could rig something up if I get a a different bolts.