Yeah, since you're using a UDS probably need to be more careful. Would tend towards pecan probably.
I have cooked briskets with Mesquite, Hickory, Oak and Pecan on my bit Horizon offset. Really not much difference between them if you're running a clean fire. Mesquite gets a bad rap. Nasty Mesquite usually due to a poorly maintained fire. At the end of the day I tip my hat these days to Oak. Just something about it that hits my senses when I'm running it. Just my $.02.