I cook mine at 250*. I cover it with EVVO, Kosher salt, fresh cracked pepper, and some garlic salt. If I am cooking it the next day, I add a bunch of fresh Rosemary and skip the garlic salt and cover with fresh squeezed garlic, and then vacuum pack. This opens the pores and the flavors permeate to the middle of the roast. I cook it until it hits 115* and take it out of the pit and let it cool for an hour. I kick the pit up to 450* and after the hour rest, I put the meat back on for 30 minutes or until a good crust forms. Take it off and let it rest for 30-45 minutes. Then I dive into it. Prime rib is one meat I do not like reheated. To me the taste changes too much. If I have leftovers, I heat them in Au Jus and make French Dips. Otherwise, I eat it cold.