Been trying to gather as much info as possible since I'm new to this style cooker and currently building one. One of the videos I came across and, cant seem to find again, had a metal sleeve basically that the fire box sat in. Majority of the videos I've found don't seem to run that set-up so I'm curious what you guys prefer and if that's recommended or not? I personally feel like I need it but wanted feedback from the experts. Thanks in advance.