I cook around 14-16 lb turkeys, and have always banked only on one side for the reasons Wampus stated above - a little to close for comfort if I have coals on both sides. I just rotate the bird about 1/2 way through to evenly brown both sides. I also go with a pan under the turkey on the opposite side of the coals. Rather than the minion method, I go with about 20 lit coals on the one side to keep the grate temp to around 350F.
UF Aero, Weber 22.5" Performer Gold w/ Smokenator