Thanks for the info!
I guess my idea of doing it while still in the car, "is" a bit of a pipe dream...but I was hoping..

For a laugh I'll tell you how I ended up getting the camaro's headliner cloth back in place..

You remember the little upholstery do-hickies that your mom used to hold arm rest covers on her favorite chair. They were clear plastic buttons, with a corkscrew wire. Yup, I used about 10 of those to hold the headliner in place. They did the job, and kind of gave the button tuck upholstery look to it. The buyer of the car didn't say boo about them.

A guys got to be inventive!