2) put a coat on your mounting bolt to keep it tight.
You'd be better off to use Loc-Tite Blue on the mounting bolt (or any rack or fender mounting bolts as well). It holds firmly but is not permanent. It's pretty much of a standard among bicycle mechanics. I have no idea what would be involved in removing Shoe-Goo from threads after a year or two since it's intended to be permanent on shoes.
Here is a link:
Loc-Tite Blue