When I brine and inject a whole chicken I get the largest I can find in the display case and usually smoke two. I smoke them at a higher temp, 300+, and it usually takes a 2-3 hours to get the IT where I want it. I really don't watch the clock. I watch the IT.
The brine is so flavorful you really don't need a rub but you can lightly splash it with anything from
Jeff's Rub to any commercial rub. My wife's favorite commercial rub is Grill Mates Sweet n Smoky. I don't put anything on the skin except a little EVOO, and sometimes I don't even use that. I usually smoke them with a stronger wood like hickory or mesquite, but that's a personal preference. Below are some pics I took a while ago on whole chickens, including a close-up of the breast to show the moistness. We started picking on the chicken before dinner and couldn't stop!
I did boneless, skinless chicken breasts and thighs this past weekend. Used a Texas Chipotle Coffee Rub I found online and put together some time ago for a brisket. Didn't care for it on the brisket but it was better than average on spare ribs and chicken.
I lightly dust BTW when I use rubs, except on big pieces of meat like briskets and pork butts.