My friend was instaling his headliner in today for his 69 Nova. Until we got to the quater panels. We stoped there cause we didnt want to over streach it like my dad and I did with our 66 Mustang. Can somebody tell me how I can put the headliner in with out streaching it by the quater panels?

use the sail panels that go there

the headliner stops at the level of the side window and goes straight back to the rear window, there are sail panels that fill that area