My studio wedging table is about 35-40 years old. Made it for my first real studio.
I cast pottery plaster into a wooden frame on a self-constructed set of table legs. The plaster is about 4-5" thick and the table is about 32" x 4 feet long. Embedded in the plaster (centered on standoffs) is a 110 VAC soil heating cable for growing plant seedlings (very low heat level) wired to a switch and a cord type plug. The top working surface over the plaster is tightly stretched heavy canvas.
I scrape the canvas when damp with a plastic putty knife. If it needs more cleaning... a lightly damp sponge takes care of it. If I am in a period of very heavy use and the plaster is getting too damp, I flip the switch overnight... and by morning.... dry.
I don't slap wedge.... I use the oriental spiral method. I've replaced the canvas only a couple of times in all the time I've had it as a FT potter. Original table, original plaster. Good investment.