Rolled boneless pork shoulder is not a good choice for smoking. Most of the exterior surface exposed to smoke is skin. While it may absorb some smoke, it will prevent most of the smoke flavour from penetrating the meat. To turn the skin into crackling that you might actually enjoy eating requires high temperature and dry heat - conditions that you usually don't have in a smoker.
I would cook it whole, with the net on. Pat the skin dry with a paper towel, then rub with salt and a little bit of oil to help the salt stick to the skin. Start with a low temperature and smoke it for an hour or so, then bring the temperature up to cook the roast to desired internal temperature. Remove the roast from the smoker and preheat a fan forced oven to 220-250C. Take the net off the roast and separate the skin from the meat. While the meat is resting, put the skin in the preheated oven (on a rack with a drip pan under) and let it crisp up to make nice fluffy crackling.
Next time you want to smoke a chunk of pork, try a whole pork neck.