I use Bard's tacky wax. I 1st found it in a local antique store then looked on line and found it there much cheaper. The label reads keeps miniatures, figurines, glass & porcelain treasures from slipping, sliding, toppling or vibrating away. won't stain wash off with warm water or just wipe off. I have used it for a couple of years and have been very happy.
I saw sombody out here talked about using a hot glue gun! I have no experience with that but I would be afraid that the shock of the hot glue on older bottles could crack it instantly, so I would be carefull with that!
I just put sticky tac on the bottom of all the bottles that are on the shelves. It works fine and Ive knocked some of them with some pretty good force by accident and they didnt fall off. That museum gel sounds interesting though since you said its pretty much invisible.