Covid vaccine card, is California digital card OK? What about testing?

I can't give you a definitive answer on the California Digital Card. I think that is a question you would have to ask the Tour office directly.
Here is the quote from the Frequently Asked Questions section in the Tour Accounts.

"Do I need to bring my original vaccination card with me on tour?
Yes, you may be asked to present your original vaccination card so we recommend carrying it with you when you travel. In addition, you should either scan or photograph both sides of your card and keep the digital copy on an easily accessible device, such as your phone.

Will I need a negative COVID-19 test prior to joining a tour?
Yes, for our tours starting May 20, 2022, and later, we're requiring pre-tour testing with a rapid self-test. Each tour member will need to show proof of a negative self-test taken within 24 hours of the first day of the tour, whether or not a test is required for entry into your arrival country. "

I am bringing one Binax Now (proctored test) in case I test positive along the tour route and need to show an "official test" to my travel insurance. I am bringing 6 other home tests and if I need more (I hope not!) I will purchase there.

Thanks for that information. Did you have to have your home test proctored?

You do not need a proctored home test for the tour. You just show either a photo of your negative test or the negative test. The proctored home test is only if I were to get a positive on the regular home test and needed an official test for travel insurance purposes.

Thank you for the information. Bringing a proctored test kit along sounds like a good idea. Have a great trip.