i did a round trip transatlantic in october and november in the princess grill. you can usually board by 12:15 or 12:30. lunch is definitely served in the princess grill on embarkation day adn dress the first night is normally casual. you will love the princess grill btw. imo it's as good as queens grill and a completely diffrerent experience from the brittania which is much more mass market. have a great trip.