We no next nothign USS Grissom other had crew of 1,250 personal. People Star Trek Encyclopedia wrote the secound ed for Star Terk encyclopedi did poor job say least. Excessor class starship does hold 1,250 people on board. It unlikley excessor class longer number crew galaxy class starship. With USS Enterpise C likley not hold more maybe 500 guess must crew killed fire fight between Romulas before they enter Yesterday Enterpise timeline logic guess the USS Enterpise C had crew 151 return normal timeline. Tons class that Star Terk exncyclopedia could choose they choose extreamly unlikley those kind number personal aboard. In pratice not even USS Enterpise D carry that many people aboard include families. May upgrade real combat Galaxy starship or inline between Galaxy class and Sovereign-class to have that longer crew.