We got two 12-pound turkeys this year, and cooked one yesterday, just for leftovers. We covered that one in salt pork and cheesecloth, along with aluminum foil, cooked for 2 hours in a 350 oven (until the breast meat hit 140). Then we removed all the accoutrements and cooked for another hour in a 425 oven to brown the skin and finish the bird (165, thankyouverymuch).
Today's turkey (the one we'll eat at dinner, serving 10) has been brining all night long in the Williams-Sonoma brine, and that'll be roasted-and-served later. Tis le yum.
We were also considering smoking the second turkey on my grill. If you need that much to feed many folk, consider two smaller birds next time. ;-)