Throw the time schedules out the window
Temp and feel is your best bet to judge doneness. Use an instant read thermometer. They're done at 160 degrees or when juices run clear when poked with a fork.
Don't be afraid to cook at the highest setting. The faster the better when it comes to small pieces of poultry.
A way to maintain mositure would be brining. Check out Smokinokies "101" (including brining) HERE
You may want to try a "spatchcock" breast...bone-in, skin-on & butterflied. The bone/skin will help increase moisture and flavor and are both easily removed for serving.
Questions? Holler back.