I do the lasso style sometimes but I always hang them on something so any leftover liquid can drip out. This is after I rinse and clean it out of course
i spin half at a time to get most of the water out. i prefer to hang my vinyl vertically, to avoid the bend memory, but there is no safe way to hold them by the end.
Alligator clip - Just solder or crimp a chunk of #12 copper wire and bend into a hook or ring or whatever. Then just hang them up on something.
They may dent the vinyl a little bit, but they won't have the pressure to cut it. I guess if it did you'd just have to cut 1/2" off your tube.
EDIT: Test tube clamp: You could bend it 90 degrees just before the jaws to get it to hang vertically. And they're less than $1.00 each with 12 or more...