I use a VPI TNT which is an oversize turntable. I believe that VPI does/did offer a quite expensive cover for it, but I simply got some plexiglass rod stock, cut six equal length legs and glued them to a sheet of plexi. Keeps most of the dust that falls off the table. A little can drift in from the sides but nothing significant.
I just lift the cover off, invert it and set it on something when I want to use the turntable.
I just lift the cover off, invert it and set it on something when I want to use the turntable.