I rub mine with cut garlic cloves and then rub with the sesoned salt & fresh ground pepper. Also leave out to get roast to room temp. Then, depending on the size, I put it into a 475 degree oven for the first 30 - 45 mins. Then knock down the temp to 325. And most definitley use a thermometer.
I stick mine in the raw roast and observe temp. as it cooks. That way your not poking holes in it that will allow juices to escape.
Serve with Yorkshire pudding and hot horseradish.