Prime Rib...

Wow, I am impressed, didn't even know they came that big! My husband is an engineer also, so... no jokes. I can identify with the research, I also do a lot that.
My experience has been with much more modest size bone-in roasts, but I have learned that an initial searing at 500* for 15 minutes and then cooking the roast to a temperature of 125* gives me good results. If the roast sets for 20 minutes the temperature rises to 130* or so.That is on the medium side of rare. The setting time is essential to let the juices distribute and will result in a more uniform color through out..
One reason for the higher temperatures cookbooks, etc sometimes give for rare is that the government standard for meat safety is to roast to at least 140*. Unfortunately that will result in a well done roast. Also, roasting a very large piece of meat at an extremely low temperature or at a high temperature inially and then turning off the oven and leaving it a long time is not a real good idea.
The problem here is that I have only done 3 to 5 rib roasts and 14 lbs boneless is an entirely different matter. I wish you good luck with your roast, let us know what you decide and how you like the results.
The method I use successfully was obtained mainly from the Beef and Veal volume of Time/Life books The Good Cook set, and an in depth article from a magazine called Cooks that is no longer available.