This thread looks like it will be a good one for the archives, so I'll weigh back in.
Sorry to hear about the poster who paid an upholsterer to install his PV headliner. Hate that when someone takes on a professional job when they aren't experienced enough to pull it off. Kind of like those guys who hang out in front of Home Depot, promising you that they are able to do any kind of work, simply because they are so desperate for the job. A waste of everyone's time,and your money, with no-one winding up happy.
back to headliners,
Joe, I like the idea of installing the screws for the visors and dome light BEFORE the headliner. A slight risk of them causing a tear in the fabric, though.
Instead of 12 gauge wire as an "anchor" for the rear window slots, I've used that rubber rope that secures plastic window screen into the aluminum frames.
Also, carpet tacks are preferable to staples, because they are less prone to tear loose. Admittedly harder to install, though.

Basically, my headliner mantra is;
1.) have at least 6 inches of excess material at the sides of the headliner
2.) make sure it is free of wrinkles and warm (lay it in the sun first) and pliable before installation
3.) make sure the "tack rails", the serrated metal pieces are in good condition, and ready to catch the material. If they are bent out of shape from removing the old headliner, they won't grab the new.
4.) work from front to back, then worry about the sides. Tucking in the sides will smooth out any wrinkles
5.) a plastic spreader, used for Bondo type filler, is a good tool for tucking in the sides. A putty knife wrapped with masking tape will do, but be careful of the edges
Ok for now? The vinyl is pretty forgiving, but work slowly. It's one of those jobs where the finished product is a joy to behold every time you behold it!