Good package. It allows us flexibility in boarding the type of bullet trains we choose (Nozomi, Hikari, Kodama). If you want to secure good seats, arrive and queue early at the platform. If the current train docked at the platform does not seem to have good seats, you can board the next one provided you are not in a rush. Recommended seatings are the ones near the front or back, the right seats of the train (if you want to see Mt. Fuji).
Reference for Shinkansen non-reserved seats: https://jprail.com/travel-informations/travel-tips/reserved-seat-vs-non-reserved-seat-how-to-get-a-seat-on-non-reserved-car.html