Hey Tony, was just trying to help as Dave was thinking about fabricating one. If you get the metal too thick will not slide into the side rail assemblies, right? Was not sure if the smoke would get around it. But, am not really keen on cold smoking so cannot say one way or another. But, if there is enough room from the back to the back of the cold plate and the front door and the front of the cold plate that the smoke can travel around then there would not be a problem in making it the same size. I would still go with a light metal, rather than one made of hardened steel as it would be pretty heavy depending on the thickness of the plate :-\.