Thanks. Yes, the smooth one is vinyl coated polyester. Nothing like "vinyl" as you normally think of it. Very tough. The other looks permeable but it is actually also coated, but on the reverse side. I would bet they are both waterproof, except where my sewing machine punches holes! I agree on the pad thickness. I think it needs to stay around 1/4"- just a bit of comfort but also able to be rolled/folded for storage if need be.
No problem on waiting. The way this is shaping up the pad will be an easy add on to either the LINE-X or the Richlite cover. I still have you down for tan LINE-X for now.
Additionally, the snaps would make a good spot to snap on some utensil rolls or similar that could hang over the end of the gate while camping. Hmmm.