Lay the butterflied pork loin flat on a large cutting board. Cover the meat with plastic wrap. Using the smooth side of a meat mallet, pound the long edges of the pork loin to a thickness of 1/2-inch, about 1 1/2 inches deep. (Flattening the outside edges will make the meat easier to roll compactly.)
Remove the plastic wrap. Season the cut side of the meat with Traeger Pork and Poultry Rub. In a large frying pan over medium heat, saut the onion, fresh fennel, and garlic in the olive oil until they begin to soften, about 5 minutes.
Add the sage, rosemary, fennel seed, orange zest, and red pepper flakes and continue to cook for 1 to 2 minutes. Let cool. Stir in the cheese.
Distribute the onion/fennel/cheese mixture on the butterflied pork loin, leaving a 1 1/2 inch border on the long edges of the meat. Starting with the long edge nearest you, roll the meat up, jelly roll style. Tie at 2-inch intervals with butcher's string. Oil the outside of the porchetta with olive oil, then season with Traeger Pork and Poultry Rub. Place in a roasting pan on a rack. (If you do not own a rack, improvise one using whole carrots or thick slices of peeled onion.)
Drape the porchetta with overlapping bacon slices. Pour the wine in the bottom of the pan.
When ready to cook, start the Traeger grill on Smoke with the lid open until the fire is established (4 to 5 minutes). Set the temperature to 325F and preheat, lid closed, for 10 to 15 minutes.
Roast the porchetta, uncovered, for 2-1/2 to 3 hours, or until the internal temperature of the meat is 155F. Transfer to a cutting board. Let the porchetta rest for 10 minutes.
Remove the bacon (you can serve it with the porchetta if it looks appetizing) and the butcher's string and slice the porchetta into pieces approximately 1-inch thick. Arrange on a platter or plates and garnish with herb sprigs and orange wedges.