A trick in the BBQ world to help get extra crispy skin on wings is to use baking powder or cornstarch as well. Add it to your dry rub and coat the wings.
It's best to allow the wings to rest like this uncovered a minimum of 2 hours prior to smoking. I prefer to even do this the day before for best results in both flavor and texture.
This smoking process will involve two different temperatures. The first to allow smoke to adhere to the wings and the second to render the fat and get the skin crispy.
Smoke at a low temperature of 225 F. until the wings are around 150 F. internally. Then increase the heat to 425 F. until they hit a temperature of 175-180 F.
Wings are dark meat! While chicken is safe to eat after 165 F. the tendons and connective tissue in the wings are best texture wise when they hit around 180 F.