I ran a steady 5 hour 325* at the grate yesterday (standard method, one full lit/one full unlit, three chunks of cherry) with my Pitmaster IQ-110 set @ 325, the other two vents at 1/3 open with the top vent open 100% for a 22 pound turkey. Used the second probe from my Weber-style dual probe wireless to measure grate temp. Never budged the whole time, never touched a vent until I was done and shut the WSM down. These things are amazing! (18.5" WSM)