BBQ Brisket Reuben Sandwiches

Name: BBQ Brisket Reuben Sandwiches
Ingredients: 1/2 cup sour cream; 2 tablespoons prepared dill pickle relish; 2 tablespoons ketchup; 2 tablespoons chopped fresh chives; Salt and freshly ground black pepper; 1 cup ketchup; 1/4 cup Worcestershire sauce; 1 1/2 tablespoons cider vinegar; 3 tablespoons dark brown sugar; 2 fresh bay leaves; 2 large cloves garlic, finely chopped; 1 teaspoon smoked sweet paprika, 1/3 palmful; A couple pinches ground cloves or allspice; Lots coarse black pepper; 1 1/2 pounds thinly sliced cooked beef brisket; 1 (16-ounce) package prepared sauerkraut, rinsed and drained; 8 slices good quality marble rye bread or 4 wick rolls (caraway and salt seeded buns); Softened butter, if using bread rather than rolls; 8 slices Swiss cheese (recommended: Emmentaller); 4 big deli pickles, for serving; Radishes, halved and salted, for serving