I made a quick clamp for my foam saw to cut multiple pieces at the same angle to be glued together. I'm making the centers on a bench seat soft and the sides firm, kind of like hidden bolsters for a premade cover. It worked well.
I work at a shop with a foam cutting table with plexiglass table top surface so we can spray it with silicone and it helps aid in gliding foam on the top. Easy to clean up too!
Ya the plywood isn't very slippery at all, but worked for what I was doing that day. I'll try some counter top stuff next time when I have to cut some shapes. I see people use band saws too but that would just be something else taking up floor space, this thing folds up and away as it is on a saw horse thingy for glass.