Place 4 bread slices on work surface, and spread top side of each piece with mustard mixture, reserving 1 tablespoon of mixture. Top with 2 slices each of ham, turkey, bologna and pepperoni. Top 2 of the 4 stacks of meat with 2 slices each of American cheese and other 2 with 2 slices each of Swiss cheese. Top American cheese with pickle planks, and top Swiss cheese with tomato slices. Top pickle planks with 2 leaves of lettuce, and top tomatoes with remaining 2 leaves of lettuce. Spread remaining mustard mixture on 2 remaining bread slices, and place 1 each on top of the bread with meat, Swiss cheese, tomato and lettuce. Carefully place each of these assembled sandwiches on top of the bread with meat, American cheese, pickle planks and lettuce, forming 2 layered sandwiches.