I'm not saying I'll never brine turkey again, but... If you're smoking a frozen turkey (yes, thawed...comedians), check the ingredients on the wrapper. If sodium is mentioned, its already been injected. For my tastes, brining this bird has in the past, made it too salty.
The towel and cooler thing intrigues me...I gotta try that one.
I had trouble getting my bird's internal temp above 150-somethin'. Others have recommended 300-350 degrees for the smoke chamber, I was running about 100 degrees cooler.
I injected the night before with garlic oil, beer, cayenne as suggested in Smoke & Spice. They also suggested wrapping the bird in cheesecloth and keeping that cloth damp. About every half hour I sprayed it with apple juice. I fueled with lump, a few chunks of hickory and about 6 handfuls of apple juice-soaked apple chips, a handful added each time I sprayed.
Except for the temp thing, which I resolved in the oven after 14 hours in the Bandera, it got raves. 180 degrees and she is done...kill that salmonella, brother.
Good luck,