I haven't seen the article you refer to, but I'm guessing that CA would dry slower in a small toothpaste cap since there is less surface area exposed to the air. I'm not sure how CA dries. Some glues cure chemically and don't require air to cure. Epoxy comes to mind, but I'm not sure about CA.
Personally, I just stick a piece of masking tape on my bench, squirt a couple of drops out, use it, and peel the tape up and throw it away.
Not sure how much paint you need at one time, but perhaps something like an egg carton might be better. I don't do much hand brushing, and the quantity of paint I use is so small I just put a few drops in an old film container lid.