What about making them out of sewing/craft beads? (or pantograph insulators?)
I know there are white and clear green beads ;blue too.
They come in many sizes.
(measure O.D.s & stack height etc. I might have a few hundred old ones hiding in a button box, white for sure & I think various sizes/colors too, maybe green. These were originally in a plastic parts drawer box(organizer...not so organized) with old train parts in some, so may be why they were there.
If not acceptable, I do wish you good luck hunting.
