I too formerly worked in a dinner house and have cooked oodles of prime rib. We used the salt method described above, and it might be the most fool-proof, tasty method ever developed. We used rock salt, which I think is better for this. We just slathered it on, using enough to send a doctor into a fit, but it never tasted salty.
IMPORTANT--PLACE THE ROAST FAT SIDE UP, THEN PILE ON THE SALT. I like letting the meat rest about 10 minutes after cooking.
A couple of other hints--yorkshire pudding is a traditional side dish, but it needs to cook at a much higher temperature, so don't even think about cooking them together. If you have only one oven, then wash some russet potatoes, poke a few holes in them, and put in the oven 60-90 minutes before the roast is expected to be done, depending upon the size--niced and easy, and no pots to clean.
For the horserahish sauce that is often served with prime rib, just mix some prepared white horseradish into sour cream to taste.
Barbq and spits too can turn out some wonderful roasts, but those methods are trickier and the ending times less certain, due to the indirect and fluctuating heat.