In a large skillet, bring Worcestershire, chablis, butter, black pepper, cayenne pepper and garlic salt to a boil. Add shrimp and return to boil, stirring occasionally. Remove from heat. Allow mixture to sit in pan for 15 minutes (shrimp should be pink).
Meanwhile, mix both cheeses, mayonnaise, celery, onion and onion tops in a large bowl. Place half the shrimp and the liquid from the skillet into a food processor and pulse until very fine. Add remaining shrimp and pulse briefly so remaining shrimp stay fairly coarse. Add shrimp to cheese mixture and blend well. Add just enough milk to reach desired consistency (thinner for a dip, thicker for a spread). Refrigerate overnight. Mixture will thicken, so thin with a little more milk just before serving.