The reason I go 200 degrees is because the size of the chuck roll is twice that of a brisket. Unless you have a foot long thermometer it won't reach the center. There is no reason what so ever to inject the meat either. The chuck is a much more porous meat and has fat throughout, unlike a brisket. So you have a 30lb piece of meat self basting throughout the entire cooking process. As That ole boy, David Wade from your neck of the woods use to say; "it is soooooooo gooooood!!!!