I measure the temp at the vent, and actually prefer about 250* for most cooks....235-250* measured there seems to work best...cooks not unnecessarily too long, but most connective tissue is cooked out of the butts by pulling time and the meat seems to be just as moist, if not maybe more, as if cooking slower.
I usually have my grates full, and if my top vent is at about 250, I've learned that the on bottom grate outside the perimeter of the pan the temp is somewhere around 275, and that's fine.
Still learning!
<span class="ev_code_RED">Yeah! I definately am still learning. After a cook yesterday where I didn't rest the two big 9lb+ pork butts before pulling, even though there was substantial fat and connective tissue left unrendered, the bbq was some of the best I've done in all aspects. I smoked both of these butts for sixteen hours, and incidently, one of them temped at 198* when pulled off the grate, significantly higher than my usual IT of around 190*. I now feel pretty confidant that I've been overcooking by the time my bbq was actually pulled for a meal, and will be more conscientious of holding meat in a hot cooker for hours at a time. </span>