No need to cover. Just smoke low and slow. For a sirloin tip, I generally pull it at a much lower temp, about 125-130, but then again, I like my roast beef to be on the rare side.Nice. Did you cover it or anything in the smoker? I have aluminum pans like that but I was considering covering my meat with aluminum foil loosely so that the smoke still gets in but won't dry it out. ??