To "old volvo owners" it need not be said, but any time we have the door panel off we should be cleaning the debris from the bottom, making sure those drains are clear such that no appreciable amount of water could be trapped inside the door for any length of time.

I was in the doors of my 79 recently to replace the rotten foam speaker surrounds on the 24-year-old originals. Found the old paper vapor barrier in one piece but so fragile it was a jigsaw puzzle by the time I had it out of the car. Made a pattern, like you, but not with my precious homeland security plastic (smile) but some heavy waterproofed kraft paper some parts supplier had used to stuff the box full. Then attached it to the door with a sparingly small amount of that homeland security brand duct tape. Shame on me, I did this a month ago before I knew how valuable these materials would be... Seriously, I figured the paper would be all right if a similar material almost made it 25 years. But those scrapers are shrinking...