I have a BSKD with many of the commonly recommended modifications, and it performs quite well for me. But during the colder months it is a bit of a challenge to maintain adequate temps. After seeing BBQEngineer's double-walled masterpiece, I was wondering if I couldn't try to insulate my smoker. I don't have the equipment or the skills to do any welding, by the way. My idea would be to wrap the smoker box (not the fire box) with a ceramic blanket material (like BBQEngineer did) and cover that with something else. Would concrete backer board normally used in showers and baths be suitable? Anyone ever tried anything like this?