Man, I was thinking the same thing - that smell brings back some memories! The day the cushions arrived, I tried to keep them in the house to give the house the smell - the wife told me to take them to the shop after about 4 hrs! At least it stayed in the house until the next day anyway. What is the smell - Canvac?
I did the same thing after leaving it in the sun for a couple of hours - measured the center of the cushion and located the first hole there with an awl (in the center of the tab). Then, I worked my way out to the ends. Then, I did the bottom side the same way. It ended up stretching about 3/4" - still too short, but I think I can live with it. I should have stretched the bottom cushion too (it has a couple of wrinkles in it).
Since, it seems, that all of the rear seats have the holes, they must have been there for a reason - drain hole seems like a logical reason for them.
Here's a couple of pics of mine:
