Lay ribs flat on the racks, bone-side down. IMO, no other way to smoke them! This does 2 critical things: First, it shields the meat from the heat source below. Secondly, the fat rendering in the meat
stays in the meat! If you hang them, or lay them on their sides (in a rib rack), the fat drips off. Instead of keeping that wonderful rib meat moist, it ends up in the drip pan...what a waste of good pork fat!