I am still new to smoking but maybe I can ask a couple questions to give more info for the more experienced.
1) what kind of smoker do you have ?
2) Have you ever brine'd before ? My experience that 24hours in a nice saltwater brine (plus you can add spices to it), the butt will absorb the moisture and spices, it does make a difference IMO.
3) Pull from the brine, pat dry then put on your choice of rub or marinade and let it sit overnight. After that, then rub right before you put in the smoker,, IMO doesnt add much flavor to the interior of the meat but it does wonders for the outside layer or bark.
4) I have never used Cherry so not sure of the flavor it gives. Mesquite can have a strong smell,, maybe a mixture of the 2 ?
5) Get your smoker up to 225, make sure you have a quality thermometer for both smoker temp and meat temp. When it hits 195 to 205 internal temp, it is ready for pulling. For that size,, if you have a good thermometer,, trust it,, go for internal temp and not time. Could take up to 20hours. The last 2 I did at that size took a little over 15 hours.
I use an older electric MES,, so my steps may be different then yours. Hope some of this helped,, the elders on this site will be able to help more :)