A use for pork skins? (post-cooking)

We've read a lot about cooking pork skins, and would like to try it. There's even a recipe for it in Myron Mixon's book. However, most of what we've read instructs you to use uncooked skins, cut them into squares, and bake them over a cooling rack or smoke them. What we'd like to be able to do is cook a whole pork shoulder, skin & all, then peel the skin off and re-smoke it from there. A few tests have so far been unsuccessful. The skins turn out either burned and crunchy, or tough and chewy. Anybody have a method to produce crunchy but not burned skins from a shoulder that's already been fully cooked?

We'll give it another try. I think what's different between what you're describing and what we've been doing is the fat scrape and the cook temp. We haven't been scraping much fat off, just tried throwing them back on the smoker assuming the fat would melt off on it's own. Also we've been cooking them on the hottest part of our smoker (basically a direct-heat cook) thinking that's what it would take to crisp them up. I'll give it a try on a cooler spot after scraping the fat next time.

I'm sure it varies a lot, but would you have a general idea of how long it takes?

Thanks for the tips!