I have to add that I have probably cooked close to 100 turkeys in my cooking career and have never had a dry one. My turkeys have ranged in size from 12 pounds (smallest) to 33 pounds (a large fresh one.) They've always been tender and moist but, being curious by nature, I tried brining and was pleased with the results.
And, as with people, I don't think there's a set rule about brining solutions, salt types and salt quantity. All brines can be different. I believe that you should use the one you like and works for you. That's my story and I'm stickin' to it.