Denny, have you ever installed one of the reproduction headliners with the free floating center retainer? They come flat and need to be bent in two different planes at the same time, while at the same time you need to keep both halves to stay inside of the center retainer. Very frustrating work. You are correct that you cannot install one with the windlace in place. If the cardboard pieces were preformed, the job would be a breeze. If the assembly guys had to do what we have to do, then it is no wonder why they were drunkards and only lived to reach into their forties.
Carl