Here is a pic of Brian installing the "A" pillar piece. You can see it is tucked into the windshield molding, but the side window part has a rolled edge that was just too fat to get the windlace over. The main top part of the headliner has what appears in the pic to be wrinkles, but they are indentations for the sun visors. The headliner has what they call a "carbon fiber" pattern. It might not have been my first choice, but I admit it looks pretty cool.
One of the time-consuming tasks was to find the holes for the rear view mirror and sun visor screws. I found them for the rear view mirror, but have not yet found them for the sun visors.
Another job that took a lot of time was reattaching the upper seat belt brackets. It was just my bad luck that I chose the spot for this bracket that was right at the overlap of the headliner and the "C" pillar piece, so that I had to locate the hole and drill/cut through both pieces for the bolt to pass through. The headliner is made of fiberglass with a foam/cloth covering that was hard to get through.
Nevertheless, I eventually got it, and here is a view of the nearly finished job. The windlace still needs to be installed above the door, but that shouldn't be too difficult as the headliner is thin in that area. The part of the seat belt left hanging still needs to be attached alongside the front seat.
Altogether a pretty frustrating day, but the headliner looks pretty good, and the color is a lot nicer than the original black.
Edit: This afternoon I found the holes for the sun visors:
The photo makes it look like the visors are grey with a black trim, but it must be some kind of trick caused by the flash. They are really black, with no contrast from the trim.
I also got one of the seat belts completed. It works and fits pretty good, but makes the rear seats even more inaccessible. I understand now why the Mustangs originally came with such thin and flimsy driver and passenger seats. It was to help access to the rear seats.