Nothing is fool-proof to a talented fool. Unfortunately I believe that you will have to take the headliner back out to make a successful installation template. Tim seems to have a good idea in my humble opinion.
1953 Chevrolet 3600 Fried Green T'mater (Vern) In the Stovebolt Gallery Caution: Political Statement Man who runs in front of car gets tired, man who runs behind car gets exhausted.