As a bonus, you can buy decent sized tubes and use them for many months. SG tubes are basically disposable once opened, since they'll be useless when they glue themselves shut or crust up.
Yes, the Shoe Goo dries up whether you put the cap back on or not! I wish they had a smaller tube version so I could more easily justify the cost. I've used Shoe Goo to repair so many things (favorite was a microwave oven handle) and never had a failure.
The key is to be prepared when using it. Wear nitrile gloves and squirt two equal size blobs next to each other. Mix thoroughly and quickly with a small, disposable stick like a matchstick or large nail. This can be used as the applicator as well. You want to mix on something non porous and disposable: I use aluminum foil for small amounts. Don't use plastic for the mixing container, as I've found it sets it faster. Don't mix more than you can use in a few minutes, because it will become unworkable quickly.
Hold or clamp for 5-10 minutes. It will hold after that, but overnight for a full cure.
You can greatly extend their lifetime by storing them in the freezer. The metal ones then die by leaking once you have used them a few times, but the plastic ones can be used for years if needed.