There's this thread and the lessons from a long brisket cook that was ruined by radiant heat from the drip pan.
So, I got the upper grate and used a maverick to monitor the grate and meat temp. I'm happy there's only a 5f difference between the upper and lower grate. A 9lb pork shoulder went on at 10:30pm, 225f, at 6am it was 150f and I was concerned it would be done before noon (messing up plans). Well it started to stall and after the stall the increase was very slow. The 1 Star kept doing it's thing and at 6pm, at 188f, I turned the temp up to 275f to get the job done, which happened.
So my question is...almost 20hr to smoke a 9lb shoulder? What is there to know about using the upper grate?