I had thought about the grommets, even bought some.
I looked at buckles, D-rings, etc, as well.
While I was fitting it and contemplating and adjusting and looking.. I realized that
1. I don't sew worth a plug nickel.
2. I had it down pretty good with just the bungie cords I was using for "temporary" hold down.
Soo.. took it from there. I wanted "easy off, easy on", but not "easy steal". I did not want to have to pull it off to go into a store for 30 minutes.. and once I had it off, where would I put it anyway? I would have to keep a saddle bag empty.
Replaced the center bungie (that went over the top) with a steel cable. If somebody wants it, they will have to cut that cable, or the sheepsking. The rest of the bungies were left as described above. And added a snap on the back.
To get it off, release all 5 bungies (one end only, easy to get to. The other ends are permanently attached to the steel cable for 4 of them. The front one has an end permantly attached under the seat). Unlock the steel cable, undo snap, and it's off. Could probably do it in 30 seconds or less if in a rush. But I should carry a piece of plastic if really in a crunch.. good idea.
Of course, I keep an eye on the weather as well!