I have done 2-3 smokes on my WSM and still haven't purchased a digital thermometer so that I can measure grate temps vs. lid temps. On the Virtual Weber Bullet site I followed the recipe of the Renowned Mr. Brown and it indicated that a lid temp of 250 had a grate temp around 237. However, I saw another post on here that someone had a lid temp of 250 and they had a grate temp of 300. In other WSM owners opinions, which one do you find to be correct? My last smoke, I kept the lid temp at 250 throughout and I had great results with 10lbs of pork butts, so I figured I was at around 235-240 grate temp throughout most of the cook.