We used an 11+ pound pork shoulder (with skin and bone). Salt, pepper the pork, leave in oven 8+ hours, take out, rest, crisp in ripping hot oven. That’s it.
“Ultra-Crispy Slow-Roasted Pork Shoulder Recipe”
We used a chimichurri sauce (different than the one recommended, only because I did not see that one) and a sweet/hot mustard sauce. I modified the mustard sauce recipe to replace some but not all of the brown sugar.
So you got one with the skin still attached? I never see them that way here. Usually just a thick fat cap. 
My wife got it from our local “higher” end store. And she didn’t even have to ask for it. Shocked me, too, as getting the skin on seems tough.
I have to say that this trend to have everything be boneless, skinless, trimmed of fat, etc., is not good.
I say “higher” end store because everything in the meat section is higher quality than other stores, but this store can be cheaper for a lot of things than “normal” stores.