Glad to see this being discussed!
I am new here btw - just bought my first Jeep yesterday, a 2000 Cherokee Sport XJ. It was a good price (I think) at $1800, but there are a few things I'll need to work on, including the apparently common sagging headliner.
What is above the fiberglass board? I would assume painted metal. Is there any reason to keep the fiberglass / fabric headliner at all?