Here's the recipe - http://www.recipetineats.com/pork-carnitas-mexican-slow-cooker-pulled-pork/. I followed it pretty much verbatim. The cook time, on high in my crock pot, was around 5hrs which seemed to track with the recommendations in the recipe and I can't think of anything that I'd really change. Even using a smaller pork shoulder (~4lbs) there is a ton of of meat for leftovers, not that I'm complaining. In the future there's a pork chilli that I'll be using this for, for sure.
In case anyone is curious - the taco construction is homemade guacamole in the bottom, then the pork, then homemade pico de gallo topped with a little cheese on top wrapped in a soft corn tortilla.