I remove nearly all the fat from my legs of lamb and replace with a layer of olive oil. You get rid of all the potential gaminess that way. Then I stud the leg with sprigs of rosemary and slivers of garlic, inside and out, assuming the leg is butterflied. Roll and tie with butcher's twine. Salt & pepper and maybe a rub of onion powder, paprika and garlic powder. Smoke at 225 with 4 ounces of cherry and a water pan to an IT of 120. Rest in cooler one hour and then reverse sear on a very hot grill. Delicious, and even better in a sandwich the next day with mint jelly.