Smoking time depends on the size of the turkey, the distance from the heat, temperature of the coals, as well as the outside air temperature. You can roughly estimate about 20 to 30 minutes per pound of turkey, but it's important to use a meat thermometer to be sure your turkey is thoroughly cooked. The turkey is done when the food thermometer, placed in the inner thigh, reaches 180° F (be sure the thermometer is not touching the bone).
Or, 160 degrees deepest part of the breast. How hot do you plan to smoke?
This also, if you are smoking for 30 hours:
Food safety is of primary concern when smoking turkey. Turkey breasts, drumsticks, wings and whole turkeys are all suited for smoking, although for safety's sake, stick with whole turkeys that weigh 12 pounds or less. A larger turkey remains in the "Danger Zone" - between 40° F and 140° F for too long
This is from the interwebz, but it sounds legit. I'll bet your bird will be done in less than 12 hours, depending on the temperature you smoke it at.