My own solution for glue-up covers for work benches has worked quite well for the last ten years – thin linoleum from a big-box store.
The thin, limp varieties of linoleum lie completely flat, and the thickness is consistent so it doesn’t affect the accuracy of glue-ups. And it is cheap – though my original cover has lasted ten years. Makes a good cover for table saws or any other horizontal surface which you want to use, or to protect.
The photo also shows how I make the caster-equipped bench absolutely solid, and compensate for an uneven floor, without fancy variable height adjusters on the workbench. I put a “U” around each caster, with a height just enough to lift the caster off the floor: the bench, all 600 pounds of it, is rock solid. If the floor is uneven, mark your favorite spot for it and trim the height of the “U’s” to make the top level both ways.
Just visible on the shelf below the bench is a wooden lever, about 12:1 ratio, which allows me to lift either end of the bench easily with one hand while I slide the “U’s” in or out one at a time. It just takes a minute.