I've cooked a turkey breast but never a whole turkey. What you also need to be aware of his keeping the turkey out of the Danger Zone, which means the IT must be 140 degrees or above within 4 hours. Otherwise you're looking at potential bacterial contamination which will render eating the turkey unsafe. Keep a close watch on your meat therm. Consult a chart about cooking time. A 12-lb. turkey shouldn't take (relatively) that long at 225, which seems like a good temp to me.
We tried brining our turkey two years. What resulted was an overly-salted turkey. My wife just places aromatics in the cavity and shmears mayo or butter or oil on the skin and rubs on various herbs. She won't let me use an injector, tells me I can only use it on roasting chickens since this is HER recipe. Harumph! She then cooks it upside down in the oven. Her finished turkeys are among the best I've ever tasted.
You could try apple, cherry, hickory, oak, or mesquite wood chips or some combo of your own making. Pecan is a very popular wood for smoking pulled pork and pork ribs in the South.