Harley,
Looks like you already have your answers. Personally, for me, butts have plenty of fat, so you're not going to loose much moisture, what you will get is more bark and certainly expose more meat to the smoke.
The CS is great for butts because it holds such high humidity.
I've even gone so far some times as to cut the really deep just to get more rub and smoke in. Butt...I also like to mop those to get more flavor inside.
Smokin'