When I do whole chickens, I get the butcher to split the chicken at the spine, so it opens like a book. Then, I rub the herbs,garlic, spices and fat both over and under the skin. I usually give it at least overnight, but this weekend it's going to get closer to 2 days in the rub. When you roast it outside, be sure your coals are not directly under the birds...keep the heat medium and roast them slowly.
Enjoy!
Having them split at the back makes them roast a bit faster...when they are spread out on the grill, it's a flatter surface. Cook them bones down, breast up with the breast closer to the center or heat..