I tend to stick to the same recipes I would use in an oven but smoke them. I don't like a BBQ rub on lamb I like fresh garlic, rosemary, mint, lemon juice, lemon zest, olive oil, red chillies, and a good kalamata olive processed into a paste then rubbed on the meat. Wrap in plastic wrap and let marinate over night. Smoke at 200F until 135F-140F for medium rare. Longer if you want it cooked more.
Make sure to let it come to room temp before smoking. Maybe 2 hours or so on the counter. Let it rest 30 min after smoking before slicing. And always serve with tzatziki sauce!