Arso, I guess I wasn’t clear. The sources are all in the sicha shoftim 5751. What I meant was not physical advice, but rather someone using Nevuah to tell someone else something regarding physical matters which they wouldn’t have known otherwise. Like Shaul and the donkeys, and obviously more weighty things as well.
The other thing, I think many other Tzaddikim and Rebbeim pre the world war did this, it was quite common then. I’ve heard the same about the Baba Sali. This is not something unique to lubavitch, although after the war it was alot more rare it seems, for someone to have directed others in this area with certainty, not just as a brocha or wish which is also beautiful but not on the table