Mix salt and sugar in a small bowl.
Sprinkle the rub over the pork shoulder 1 to 3 days before grilling.
Score the skin in a crosshatch pattern if present and rub in seasoning.
Refrigerate uncovered and bring to room temperature before cooking.
Soak wood chips in water for 30 minutes.
Place a tray of water under the cooking grate on the unheated section of the grill.
Adjust burners to maintain a temperature between 95°C and 150°C.
Place drained wood chips in a smoker box over the heat source.
Position the pork on the grill above the water pan with the fat side up.
Cover and roast for 4 to 6 hours until the internal temperature reaches 90°C.
Crank heat to 260°C for a few minutes if crackling or bark is needed.
Rest the meat for 20 to 30 minutes before shredding.
Combine vinegar, water, sugar, salt, and peppers in a bowl for the sauce.
Pull the pork apart and mix with a splash of sauce before serving.