The spindle with a bobbin that I tried works best with a spindle with a straight rod spindle. I am not sure if there is a way to get one to work with a curved or tapered rod spindle. I don't have a spindle like that, all of mine are simple.
The o ring snugs the bobbin in place. If you don't have an o ring you could try a rubber band.. It is a bit more work since you have to double..triple..etc the rubber band. Here are some close ups.. The first is the o ring the second is the rubber band... Notice they are both under the bobbin somewhat. That is how they snug it up