I forgot to post this above also you are going to want to get a back for your rack after you install your flex watt. It will help keep your Melimine from sagging and help keep heat in on the back side.
Also the back is going to help keep your rack square, otherwise if you lean on the rack from the side you put stress on the rack and it could break. you can just nail it on with some small bradsabout 1 inch long.