I used 1/8 inch to floor a 1648 g 3 last month. I also put 1 and 1/2 inch blue board insulation under it for added strength and sound dealing and you want to do that also. I used a Sabres saw with a wood blade to cut it. If you use a metal blade, they get too hot and load up with aluminum and can't keep them cleaned out. You will run thru a lot of metal blades and aluminum is soft enough for a wood blade to cut it.