Went to my family's quiltshop today and did some sewing.
Props to Slandis for the idea to use PEX tubing for the ring.
These should fit in any 4in sock holder.
Made two different kinds, one medium and one fine. Didn't bring the camera with me, next time I'd I made a few I'll do a step-by-step. If anyone wants one they are $2.50 each.