I buy whole sheet A4 sized shipping labels on EBay, usually boxes of 100. Can't remember the price but pretty cheap. But, here's the thing, I always sand the face of the plywood to 420 grit before applying it straight on to the wood. When it comes to removing, a QUICK wipe with Turps Substitute, leave for 2 minutes if needed and then peel. Job done.
I have noticed that if the surface of the ply is NOT sanded and left as is from the maker, when peeling the paper it tends to lift slivers of the wood. I have attached a pic of the latest piece I made. It was designed, printed, stuck on the ply (after sanding) and cut, pattern removed and glued up all in one day. I was happy with that as at 80 + years old I don't get about the way I used to. It is made from 1/4" Birch Ply and about 200mm (8") in diameter.
take care and stay safe
Don W