If I use the butternut squash, I can call what I smoked in the little WSM "Soup to Nuts."
I got very good performance on the 14.5 WSM using lump. With no water in the pan and one bottom vent open, it held over just over 250° for nearly 5 hours.
In the 18.5 I got some ribs hanging.
With one bottom vent open, it's cruising along at about 250° too (At two hours, 245° at the lid and 275° using a probe through the mid section. In the rain.
I'm surprised both cookers are doing so well in the rain!