I installed the new polyurethane tack strips above the doors. On each side there are upper and lower strips, and I decided to replace only the lower ones. Then I started installing the headliner. This is very tricky, since it has to be smooth and tight, without any bumps, dips, or wrinkles. Part way through, I decided that I could not trust the original upper tack strips above the doors to hold it in place. So I made some more plastic ones and installed them. Then I realized that I really ought to install mounting points for front shoulder harnesses, since it would be much harder to do after installing the interior panels. I made some reinforcing places from steel strips, with a mounting nut welded to them. These were fitted on either side, above the rear doors, just behind the B-pillar. On more modern cars the mounting point would be on the pillar itself, but on my car the front seat is too far back for this to be an effective location. Once all this prep work was done, I finished stretching and stapling the headliner all the way around.
The next step is to start fitting the interior panels, and the windlace around the door openings. Some of the panels are a little bit too large, and I will first have to peel away the fabric from the back surface, cut off a bit (1/8″) of the cardboard all along the edge, and glue the fabric down again. I started doing this; it is tedious and requires a lot of care to avoid messing up the fabric.