Concrete copying is an excellent way to shape your pool, i would think because it is more uniform with the deck, and overall shape of your pool. I work with the styrafoam, and it has worked amazingly. It all depends on who the company is that will be doing it, and how much time they wait before taking it off once it stiffens, tamping it in the front and using a piece of the actual form to seal and fix inperfections. By the way Sean, may i ask who is builind your pool? Because i see your from NJ too?