Check these out. I think threaded studs would work better for the rack.
https://herbiesaudiolab.com/collections/loudspeaker-rack-decoupling-and-isolation/products/threaded-stud-glider?variant=12651505680439
https://herbiesaudiolab.com/collections/loudspeaker-rack-decoupling-and-isolation/products/threaded-stud-glider?variant=12651505680439