OP, whenever I purchase Avanti seats, I buy direct from Avanti's site because they sell the Standard Premium tickets at a reduced rate for some seats. You have to click and find them, but it's very much worth it. These carriages are the same seats as First Class, and you can reserve your seat. They always have plenty of luggage room. I travel with large luggage because I am usually there for weeks at a time. This is more affordable than doing it when they come to check the ticket, I believe. Sample I just ran for a random one-way in June. It did not come up for all routes that day, so choose accordingly.