The answer to your question about what do the shops do, is they are using a two post lift. The front lift arms go under the subframe horns that turn up below the firewall and they throw the rear arms under there anywhere in front of the rear wheels. There is a beam that runs the rear portion just inside the rocker panels.

That said, that's how they do it in Texas where we have rust free cars. Since your car has rust damage, I think you need to make some shoes or whatever it was that Luke called them. It would be easy enough to simply slide a piece of thickwall pipe of a size that would fit well into the jack tubes. Then pick it up a small distance with those. If you pick it up too far, the pipe might tend to slide out. I don't know how you could go about locking them in position.

On the earlier cars I used to simply lift up the back by the differential center section. Doing that on the later cars, however, will eventually destroy the differential mounts. These mounts are a &(*%_ to change.

Good luck and Merry Christmas,