Despite the sheet rolled out over it, it's not dead yet. This week, I put fiberglass on.
Unlike the inside, this time the fiberglass went on fairly easily. I rolled it out over the top, cut it to shape, and masked it off.
Then I poured clear epoxy over it and smoothed the epoxy into the glass with a rubber scraper. With a little help from gravity on the sides this worked quite nicely.
Note: this post was written long after the fact so I don't have a lot to say about this. Suffice to say, it went quite smoothly.