Like we mentioned above, if you desire a crispier skin, you can leave the bird in the refrigerator for 24 to 48 hours, uncovered, to dry the skin. The skin will start to look transparent and funky, but trust us.
Oil the skin before applying your rub and that will aid in the crispiness also. If you use smallish chickens, you should be able to get 3 birds on the large egg. You may find that the egg's temperature drops and takes a while to come back up to your cooking temperature. You may wish to open the air vents to help the fire get hot again, and then close them back up to their previous setting after the fire has returned to the proper temperature.