I just got a shoulder from Price-Rite, they had them for $0.79/lb! 8.93lbs for just $7.05!!!!
I had a really good-cutting knife I lost for almost 10 years and found it recently, it was the only knife in it's set that had micro-serrations (the rest were Laser/Ginzu style edges--I think the set was like $19.99 with the wooden block!) and was shaped like a Rapala filet knife, think it was called a fruit knife...I used it for slicing tomatoes very thin. I started cross-hatching the thick skin until it reached meat. Even with that knife, it was tough going. I figured maybe try a different knife from the current Oster set and the Oster bread knife cut through the tough skin as if it were butter!
So I ended up with a diamond shaped pattern and was able to really rub my spices deeply into all the crevices down to the meat. I put the rubbed shoulder in an "oven" bag, (didn't have a big enough ziploc), squeezed out the air and twisted it shut and it's in the fridge now for over 24 hours.