Jeffersonian, If you move your bottom ring then you won't have the lower air vent lined up correctly. I've heard some folks comment on hot spots in the rear of their eggs, but I still haven't found mine. The people who make the BBQ Guru sell a "turbo grate".(google) It's design may help to cut down on your hot spot. I'm not sure if it would help, but you may want to post a ques. to those that own one. Is your hot spot consistantly there for every cook? And have you checked to ensure that your bottom ring is lined up? I wish I could be of more help.
