I tried the headliner and gave up before I ruined it, then I hired an experience guy to do it. It took him about 2 1/2-3 hours give or take, but not a wrinkle in it. No way could I have done that, especially being my first one.
Found out the repop sail panel clips are not always in the right spot either, his little trick was to remove them and the attachment board from the sail board, put them in the holes, then re-glue the sail to it. Perfect alignment. I'd have never thought of that.