With the small wires attached to the rear bow, you should be pulling forward towards the windshield which keeps the bows in tension to prevent them from flopping over. As the side-to-side slack is tightened up, that helps keep them in place as well.
Almost sounds like the headliner isn't fully taught yet. You don't want to be hooking onto the teeth until it is.

Another thought.. did you put some type of padding on the roof skin? The bows should be in the side holes such that they are touching the pad, but not pushing up the roof skin. That'll help keep them in position as you draw up tension on the headliner material.

Do the sewing lines seem to be spaced correctly?


Rick