Butterfly and brine pork loins: Mix the brine ingredients together in a container large enough to hold the pork loins. Let the salt and sugar in the brine dissolve while preparing the pork loin. Slash the fat on the top of the pork loin by making parallel, shallow cuts about ½" apart. Butterfly the pork loins, opening them up for the stuffing. Turn the loin on its side, and a lengthwise cut, ⅓ of the way into the loin, cutting to within ½" of the far side - the cut should go almost all of the way through, but not quite. Fold this cut open, then turn your knife and continue the cut into the loin, mid-way through the remaining, larger side of the loin, cutting again to ½" from the far side. When you fold this final cut open, the loin should be an even thickness all the way across. Repeat with the second loin. Stir the brine until the salt and sugar are dissolved, then add the butterflied pork loins. Refrigerate for 2 to 4 hours to let the brine penetrate the meat.

Prepare the grill: Set the grill up for rotisserie cooking at high heat. For my Weber Summit, this means removing the grates, turning the two outer burners (burners 1 and 6) to high, and turning the infrared burner to high. Then I put my drip pan in the middle, over the unlit burners, and let the grill preheat for ten to fifteen minutes.

Stuff and tie the pork loins: While the grill is preheating, stuff and tie the pork loins. Remove the loins from the brine, and pat dry with paper towels. Spread the loin out, fat side down. Sprinkle with half the herbs and a light coating of black pepper. Top the loin with a layer of pepperoni, a layer of provolone, and a layer of capicola. Roll the loin back up the way you sliced it; the fat should wind up on top, with a spiral of stuffing inside the loin. Truss the loin in a couple of places with butchers twine. Repeat with the second loin, stuffing and tying. Now, take the two loins and put them together with the fat caps facing outward, and trust the two loins together, using butchers twine about every inch and a half. Finally, run the rotisserie spit between the two trussed loins, driving the forks into the middle of the loins to hold them steady.

Cook the stuffed pork loins: Put the spit on the grill, start the rotisserie motor, and cook with the lid closed. Check the loins after 45 minutes, and every 15 minutes after that; if they are getting too browned, turn the heat on the grill down to medium. The total cooking time will be an hour to an hour and a half; the loin is done when it measures 140*F internal temperature at its thickest point when measured with an instant read thermometer.

Serve: Remove the loins from the spit, and cut the twine from the loins. Let them rest for at least ten minutes before carving. Cut the loins crosswise into ½" thick slices and serve.