With lamb, less is more. A simple rub with celery salt and course black pepper is sometimes all you need. Of course, we have marinated overnight too (Most recently a Tandoori marinade) and gone the olive oil/rosemary/garlic/S&P route too. I'd go by internal temp and not time, not letting it go over 140 IT at the absolute top temp.
Guerry >^..^< Pit Beeatch for Team Munchkin
Avatar by Northwest BBQ
I took the Art History Comps, and Passed on the first try.