Hmmmm, I cook whole packers on my KJ and couldnt be happier. It seems a 13 pounder or close to it is the perfect size. I cook at 240-250 or close to it, until the brisket probes tender. Then I wrap it in foil, put it in a cooler and let it rest an hour or two. Unwrap, seperate the point from the flat and slice. It has been perfect everytime.
I dont do burnt ends, so no suggestion there. Try again.