Place pork belly skin side down on a flat surface. Cut roast or shoulder into large cubes and place in a large bowl. Chop all other ingredients (garlic, herbs etc.) finely and add to bowl. Add 1/4 cup extra virgin olive oil, salt and pepper to bowl and mix well. Now place contents to center of the pork belly, carefully fold both ends of belly until a large cylinder shape is created. Tie entire belly together carefully spiraling along entire outer surface and ends leaving only 1 inch of space between each loop. Cover entire belly with olive oil and coarse sea salt and place in a large tray preferrably on a baking rack. Place in a preheated 400*F oven and cook for several hours until skin is crispy and golden brown and interior temp of roast has reached 170c (use an oven probe or meat thermometer) Use the drippings from porchetta to baste skin occasionally. The size and weight of roast will determine actual cooking time. Once done, remove from oven and let stand for 1/2 hour before cutting.