oldskoolmark
Try a "half inflated" kids scooter innertube under them, complete (air) isolation worked wonders for me back in the T/T days and now with CD transport also.
Pick your size. (Tom Gillett aka: Sam Tellig of Stereophile put me on to this decades ago)
https://www.walmart.com/search/?query=scooter%20tube&typeahead=Scooter%20tube%20
Cheers George