Not tried them, but the sure are pretty..
Mines made from a piece of 3/4" poly foam that something came packed in -or- can be had from Hobby Lobby for a dollar and some change.
Used a dime and a sharpie to mark the spots and cut them with an exacto knife. They hold 10ml snug.
Used a dollar coin (Susan B) to mark for 30ml.
Finished with a coat of satin black.
Total cost, a little of my time..
But now I've got a weekend project to play with when it gets too cold to do anything else.
Scrap oak from another project, drill press, bits, polyurethane and a little of my time...