http://www.seriouseats.com/2014/12/food-lab-guide-to-prime-rib.html I recommend this recipe. You can cook to varying temperature degrees, depending on your taste. Pull at 120, 125, 130, 135, etc. But this is the correct methodology for roasting a rib roast, regardless if you like it rare or well done or anywhere in between. Because you are roasting it at 200°, you are not evaporating any juices to steam; they boil and disappear at above 212°.