We load up a full hotel pan with Ice and put it on the top self. I normally bring my brisket and ribs slightly (not hard) frozen, my chicken hard frozen, and my pork completely thawed. Coldest stuff toward the top. Keeps everything below 40* until needed.
When it's time to transition over to a warm cambro, we boil up some water and put it on the bottom level for about 15-30 minutes.
Instead of the pain of water. When you take your first big cut off, loosen foil and put in Cambro. After your desired time for 'cooling'. Take it out and wrap back up and put back into Cambro. It will be warmed up from the cooling or resting.....