hi I add one point, to advance a maximum in the searches and to save to point prometheus before leaving with the little sister.
That way you only have to take the metro to get back to old levels and find the enemies you need.
For the little sisters, you can take pictures with their protectors until you can't take it anymore.
But do not kill her or her protector, but go see another and do the same.
Do this to the final search level.
Combine the 2 tonics which increases the search during the photos if I remember well it is "eye of the expert" the normal and improve it.