I think that H.V teaching is infallible, although all the reasoning therein may need tweaking.
I think we could make the case that PaulVI had heroic courage in promulgating H.V.
I think you are confused on what “pastoral” means.
If you think HV is infallible, it is not “pastoral”; and Paul VI did nothing that any pre-conciliar pope would not have done. There was no “heroic courage” in simply holding up his predecessors’ teaching on faith and morals.