Here is what I did a few weeks ago.
Turkey Cannon Smoking Instructions
Soak cheesecloth in butter, garlic powder, and Montreal Chicken seasoning (2lbs butter for 20lb turkey).
Cook at 220 up to 160.
Unwrap turkey and take the smoker to 300 to brown the skin.
Cook to 170.
Put in a pan in the smoker. Cook 6 to 7 hours for a 20 pounder.
Good luck.