Mine ruined some V-groove F1s, had the alignment changed to my specifications as it was completely out from the factory. Didn't have the problem with the next 2 sets.
The key is here, the factory settings are wrong. If the alignment place checked and reset them against the unrevised factory settings, then they're still wrong!!
You want no toe and either the same or slightly less camber than the fronts - depending on how loose you like the back end?