I'm going to smoke two turkeys for Thanksgiving but one is 14 lbs and one is 9 lbs. I'm pretty sure the top grate runs a higher temp and I'd place the larger bird on top but want to confirm that. Suggestions are welcome!
Then you might want to consider putting the larger bird on the lower grate because you will have to pull the smaller bird first in all probability. That way you will not have to pull the upper rack with a bird on it to get the smaller bird out of the smoker if it is done first.