Easiest way of all is to not worry about the complicating filleting required and just cut the whole thing into cutlets about 20mm thick. A sharp serrated knife with a long blade will go through the cartilege like butter. Leave the skin on and freeze them till you want them.For cooking, just dust them with flour (seasoned to your taste, if desired) and throw them on a hot BBQ plate.They cook in no time, they don't curl up and the skin goes crispy and peels off easily. There's never any leftovers!