Fantastic! My mouth is watering just looking at the pic! I am sure this was a very enjoyable meal, and I like the mixture of hickory and cherry. The 18 hours to finish sounds spot on -- as a general rule of thumb, I estimate 1.5 hours per pound, and add extra time to finish early without rushing the meat.
Great job! I see a second butt going into the 3.5D in your near future! Cheers