I've decided to build our new rack instead of buying. In fact, I'm going to get the tubs this weekend. I was wondering how much room does the heat tape take up. The DIY pics I've seen show people using CDs as spacers when installing the shelves. Will using a CD give me enough clearance so that the tub wont be wedged in there too tight between the heat tape on bottom and the shelf above? I need to get all my measurements figured out before I have Home Depot cut my wood.