So I finally calibrated the dome thermo. It was 25 degrees shy of boiling. I put on the 9.5 lb brisket (slathered in Bad Byron's) when the dome hit 250. I clipped Maverick probe to the grate. An hour later, there is a 100 degree gap. Mav says 253. Dome says 355. Trust the Mav?
XL BGE; Schertz TX by way of Stow OH