Not an expert- but CPVC is used for plumbing.
PVC has the jury out and some argue it is toxic. Interesting that Sarah wrap and what grocery stores wrap meat and cheese in is PVC.
On the cheese press, I made one buy cutting two 11 X 9 boards (oak). I cut two-inch diam holes holes in the corner of one - the other I made into a little table like structure (used PVC for legs!). Turned the "table" upside down leg-up and the top piece with the holes in the corners fits over the top of it sliding up and down the legs of the "upside-down table". I put the mold in there between the legs and slide the top over the legs, I use regular weight lifting weights on top of it.