I could type a lot here, but really it comes down to two scenarios:
I critically hit with an inubrix pick. Are my dice d8s or d10s?
I am a champion of Nethys. I hold my staff in 2 hands. Are my dice d8s or d10s?
It's really just, do you apply die upgrades/downgrade before or after die changes? I'm hoping this is consistent across both here, but I'd be interested to hear why they wouldn't be.