I started with a solid piece of baltic birch, and cut 4 squares in it so that it ends up with 2.5" all the way around the edges (where it attaches to the enclosure) and a vertical and horitzontal strip in the center. Somewhat like the link you posted, but my brace looks like a frame and a cross, where the top drawing of his looks like a frame and a diamond. Can you picture what I am describing?