Hi Cold Smoke,
Just my $.02, but I might consider using a medium-to-strong wood like alder, pecan, oak, or hickory for the lamb. Alder, oak, and pecan might be safer choices since they are relatively neutral in flavor. If you don't feel the lamb gets smokey enough from one of these woods, I would suggest a hickory/cherry mix for the lamb. I would not inject, but I would FTC for 1-2 hr.
John
Newton MA