Bill-
I you want to mop, every couple of hours sounds about right. If you're using a Cookshack, bear in mind that you are going to add to the total cooking time by opening the door that often. If you're wanting to add some extra flavor, the mopping may help, but you won't need to use a mop with a CS from a product moisture standpoint.
I most likely use a larger smoker, so I'm not much help with the wood amount. Thats a pretty small cut for pork butt. I usually like to lay as much smoke as a can to pork butt, as the thick cut of meat doesn't soak the smoke into the center very well, but people's tastes as far as amount of smoke vary. If in doubt, I'd probably go light on the wood, and add more wood for your next cook if this one isn't smoky enough for you.
Good luck!