https://www.yummly.com/dish/992923/how-to-cook-a-turkey
Recommended by Sam Gasson, although not specificly about heritage turkeys.
on salt brine by volume: 3 Tbsp. Diamond Crystal kosher salt = 1 1/2 Tbsp. Morton kosher salt. When in doubt, start with the lesser amount, and increase according to taste.
Temperature: 325F if over 14 pounds
time: 16 lb: 3 1/2 to 4 1/2 hours unstuffed, another hour if stuffed
temp measurement: breast cooks faster, so most recipes suggest measuring in the thigh, but its difficult to find the right location in the thigh.
go for 175F in breast, 165F in thickest part of thigh
https://www.yummly.com/recipe/My-Favorite-Turkey-Brine-2510223
Slow Roasted Turkey with Apple Gravy and Buttermilk Brine - from NY Times. also not explicitly about heritage turkeys.
https://www.windynranch.com/blog/tips-for-cooking-a-heritage-breed-turkey
rub butter under loosened skin
Cook at a high temperature (450-475 degrees F) for less time than a regular turkey. Most heritage turkeys will be cooked through in fewer than 3 hours.
Final temperature of 140-145 F in the thigh. while resting, should reach 155.
https://www.huffpost.com/entry/how-to-cook-heritage-turkey-pasture-raised_n_5beaf261e4b044bbb1a95b36
8-12 minutes per pound, but trust your thermometer, and to check the temperature in both the breast and the thigh
recommend low and slow. 325 or below, then turn up to 400 or 425 at the end to crisp the skin
cook to 175F both breast and thigh
remove breast and keep cooking thigh+leg if needed
https://williamrubel.com/how-to-roast-a-heritage-turkey/
covering breast with aluminum foil doesn't let moisture out - steams the skin
alternate: oiled paper or cloth
better; add fat/butter under the skin
otherwise, mostly about smaller birds. recommends faster, shorter cooking time, like game birds.
https://www.localharvest.org/features/cooking-turkeys.jsp
http://nashsorganicproduce.com/recipes/roasted-heritage-turkey/
also assumes small 7-9 pound birds
rub with butter+rosemary/herbs; this makes the bird self-basting, and avoids letting oven cool off from frequent opening
oven at 425-450 F. Roast the bird until the thigh temperature reaches 140-150 F