I have a 30 pound turkey (!) to cook for Thanksgiving and I'm planning on spatchcocking it to get it to cook a faster and more evenly. My problem is I can't find any guidelines for how long to cook a spatchcocked bird, only whole birds. And while I can find recipes for roasting flat birds, they all seem to be for birds half that size. I suspect that the cooking time is less than double what it would be for a 15 pounder, but I really don't know. Anyone?