[6pack] Waterproofing door panels

[forzion at maine.rr.com]

I am about to put new door panels on the inside of my '74 my Six's doors. The old water curtains are long gone. What have people done to replace these or found a more effective way to protect the car and the panels themselves from rain? I supposeI could mount plastic sheeting to the back of the panels before inserting clips into them.... Any better ideas out there?

Dave