Chickens and turkeys are prone to salmonella bacteria. Cooking temperatures of 160 degrees F minimum are essential for destroying this bacteria. This temperature is not the OUTSIDE of the turkey but the INSIDE. I would use a water pan under the bird and set the temperature of the fire around the bird at 220 degrees F to 240 degrees F. Plan on 30 to 40 minutes per pound and use a temperature probe in the thigh to test for done. Hickory, pecan and oak are good woods to use but I am especially fond of cherry, apple and corn cobs. You can find some of the big beer in the butt chicken cookers for turkeys and they work great, you can make one from a larger tin can. Drip pans filled with water, wine and herbs do wonders for the flavor especially the woody stems of rosemary and thyme. Expect the skin to be very dark and check the temperature as often as you think is necessary to keep it from overcooking but you don't want an undercooked bird. Test in the thigh away from the bone.
For a garnish try bunches of grapes around the bird. I used to do this with roast goose and found it is outstanding for turkey. Mix the colors of the grapes.