After tracking down some 1/4-inch all-steel pop rivets (which are surprisingly RARE) and a rivettool, mix the panel adhesive (this is an equivalent to JB Weld), apply it to the edge of the plate, and rivet it into place. Allow the epoxy to cure THOROUGHLY before knocking any protruding rivet nails into the B-pillar, and collecting them from the access hole below the shoulder belt reel. I knocked all of them through to prevent future rattles.
Then prime & seal the area around the repair, paint if desired, and reinstall the interior. Both a headliner AND a B-pillar trim are required to cover the plate. I have a lot more work to do, so mine will be totally cured before I paint it.
This is why the body cracks:
