Hello jfscott
Thank you for your request.
Here you will find all the information: Enter on the Internet www.swiss.com
If you already know which flight you will tae to your final destination. Go directly to www.swiss.com then you will see directly which train it suggests you have to take, which is then binding you can’t then take an earlier train.
It says TRAIN + FLIGHT (written in red) and it automatically shows you which train you have to take.
You can also conveniently buy two saver day tickets for the days you want. https://www.sbb.ch/en/travelcards-and-tickets/tickets-for-switzerland/day-pass.html
I wish you a nice day.
Greetings, LauraV