I agree with coffeesp00ns spatchcock and cook at 500 degrees. A 10lb turkey will be done in right around an hour. Cook the stuffing separately. Why? Thermodynamics, a 10lb turkey with stuff is effectively 3+ in thick to the center spatchcocked its less than 1. It cooks more evenly because the heat doesn't need to penetrate that far in and there is less of thermal gradient. Also at 500 degress you get that crispy skin (assuming you separate it from the body dry brine it with salt and let it dry it first) As for Heritage birds, I agree with you cant get a true "Heritage" bird even at Central market or Whole foods. The birds that are Labeled Heritage are actually some sort of cross between a Heritage breed and a factory farm breed. The only way to get a real one is to either Mail order or order/pickup at the Ballard Farmers market and then they are quite pricy.