I did one (14 lbs) this past Sunday using a kettle and rotisserie, turned out great. Seasoned with Tony Chachere's, with lemons, onions and fresh herbs in the cavity. I also run my hand under the skin on the breast to loosen it up and put strips of bacon under the skin to help keep the breast meat moist.
I may try to brine next time but the results were tasty without that step.
22.5 WSM, 22.5 OTG, 1992 Smokey Joe