I made my own floor protectors. I first sharpened a piece of thin walled 1" diameter pipe. That gave me a tool for stamping out 1" diameter disks from 1/4" thick felt. I then did the stools one by one. I turned them upside down and sat them on the counter. I swabbed the existing metal feet with alcohol and also sanded each one with sandpaper. That gave me a clean surface to glue the felt pads on. I mixed up some 2 part epoxy and spread it on one of the metal feet. I then placed one of the felt pads on the foot and held in firmly in place with 2 pieces of masking tape at right angles to each other. Repeat for the other 3 legs.
I did this about 10 years ago and all 16 pads are still in place