I'm not sure a lot of people try to get it crisp. It is more of a tender and bite through skin. We did a comp over the weekend and had our best chicken finish yet and tried a new recipe where we scraped the backs of the skin and that helps. But lots of guys don't scrape and do great as well.
it is kind of like poaching them to change the consistancy of the skin before smoking. i think the pickled pig at bbqbug.com has a tutorial. many poach in a tinfoil pan but i use a mini pound cake pan to get a uniform thigh shaped look.