The key is allowing the meat to dry first. I usually stick mine in and allow them to air dry for several hours before turning it on. After that the first hour is without wood to ensure they dry. Then 3 to 5 hours with wood should be good for thick filets. Every time you check it though you add time as it releases all the smoke. By the way, I've switched to hickory chunks for kings and silvers. It's a sweet deep smoke flavor. Everyone really likes it.