"Please let me know when the Catholics decide to follow the infallible teachings of Vatican I or the infallible teachings of Vatican II."
After they quit confusing what's infallible and what isn't, and as soon as they quit believing that there are any new Catholic teachings. After they've figured out that ultimate reality in 2005 is the same ultimate reality of 1302.
When it happens, it'll be self-evident.
It's convenient technique to say whatever we decide is the right decision and if we change our mind that is the right decision as well. There are many groups who use this same argument on me before including the Eastern Orthodox-as flawed as it is.
Am I'm to assume the RCC is correct or the Eastern Orthodox is correct? Both can be traced to the early church fathers. Both claim their church is infallible. Who's infallibility is correct?