I reglued the headlining on my santorin 1994 four years ago.Cleaned the old vinyl with brush and vacuem cleaner reglued the old headlining with polyarethane sealent.(or sikaflex) This is easy and last longer then traditional glue and is less messy to work with.
Afther four years in the tropics (now panama) everything is still in place.Cheap and good solution.