I don't know that I believe Busch is a better 3B than Turner, and I don't mean that as a compliment to Turner.
I think the other thing worth considering is who is on the mound. Steele and Shota are expected to start the two games in Japan. With lefties on the mound, you expect more righties in the lineup and more balls pulled to the LF side. And Steele in oarticular is a heavy groundball pitcher.
So even if you're comfortable with Michael Busch getting some runway outside of 1B, I think generally it would be would be 3B when someone like Taillon or Brown is starting, and 2B when someone like Shota or Boyd is pitching.