I did mine too. But used 2 layers of Carpet padding over the top to keep heat down so I used any hole that would line up to the bows. One thing that I learned on a tv show, was to leave all of your screws in the holes for the Hanger hooks, shoulder belt clips, etc. Because after you put on the headliner, you can't find the holes! You think you know where the holes are, but you'll be poking around with a sharp object trying to find them, then pulling the moulding off to SEE them. If the screws are there, you just poke them through from behind with a razor blade.
Rob