I am planing on building a DVD-Rack insert for my existing built-in shelves. Click here to see My Shelves. They are all finished in sheetrock. I want to build somthing simmilar to the Boltz Racks, with the rods that span across the width of the shelf (About 40" +/- 2") and the DVDs/CDs sit on the bars. My plan was to attach two boards (3/4" thick) to each side of the existing shelf (vertically) and drill 1/2" deep holes to support the steel rods (1/4" or 5/16"). Has anyone done something like this? And if so, would like to share the dimensions for the hole layout? Is 1/4" of 5/16" strong enough to keep the shelf from sagging when loaded with DVDs/CDs? Any other ideas to hide the 3/4" board on either side of the existing shelves? Thanks four your comments and ideas!