Rolling the ribs is to allow the maximum possible racks in the WSM "Smoker". Once the ribs have got some smoke and developed a crust which takes anywhere from 1 to 4 hours. Note do not try and rush the smoke by making poor little WSM belch heavy smoke that makes for bitter food. When you are rready to foil unroll, foil and finish. You can finish in the WSM or the oven the purists know the difference the ribs are clueless wrapped in foil. Stacked flat foiled ribs cook just fine.