Those lightweight tray pans are for cutting and/or serving. You can use them for cooking, but you'll end up something that's closer to an American-style crust than NY-style, i.e.,[/] thicker, denser, and chewy rather than light, crisp, and airy. Cook at as high a temp as your oven can manage: you'll get better oven spring. Melting the pan's not an issue because the melting pt. of alum is 660.32 °C (1220.58 °F).