Pork shoulder (picnic or butt, but butt is definitely preferable here) is one of the cheapest meat cuts out there. It's also one of the most delicious meat cuts out there. As long as you cook it low (like, omg is it even safe to cook it this low?) and slooooooooowwwww, it's virtually impossible to eph it up. I used to brine my pork shoulder, but after trying David Chang's Bo Ssam recipe, I'm totally converted to the salt/sugar cure. Here I've added spices to make it a rub/cure hybrid.
The chile barbecue sauce is something I just threw together wanting to use up the plethora of dried chiles I bought on a whim in well stocked market. The chile combination can be messed with depending on hot you want your sauce. I'd say use the same total number of dried chiles, just altering the number of each type. —pigisyummy