Sometimes the amount of turn in a patters in flexible, sometimes not. The way to determine this is not necessarily by the way the teacher tells you it "has to be", but by common sense.
For example, if you're facing the wall and you'd like to turn to the line of dance, common sense tells you that the exact amount of rotation you want is 1/4 left. No more, no less.
On the other hand, if you're dancing a Jive basic and you feel like turning it to the right, you should turn as much or as little as is comfortable for you. There may be a physical limit as to how much, but certainly not to how little you turn.
Argentine Tango is a social dance style, and social dancing requires adaptability and improvisation. There are no "correct" alignments as required by a governing body; There are only suggestions as to what usually works on a social dance floor. When you get out there, you must adapt what "usually works" to what "works at this moment"... the two may or may not be the same. If you usually step forward on count "X", but there's someone in your way, you either have to adjust your direction or wait and change your step to count "Z" in order to accomodate the situation.
That being said, I think it's fair to say that you can turn your Salida anywhere from 0 to 1/2 to the left, depending on the situation. Remember, Argentine Tango was originally danced in small bars and nightclubs. Small dance floors require you to turn more (or more often) to stay within the boundaries of a small space. 1/4 might be a good amount to turn in this situation.
But when you're dancing on a larger floor, again, you have to accomodate the situation. You either have to turn less or include other patterns that help you re-align. Argentine Tango was not meant to be danced on large ballroom floors, but because it is flexible, there's nothing preventing you from doing it.
As far as suggesting other patterns for re-aligning, I can't help you much there. My knowledge of typical Argentine patterns is pretty limited. Maybe someone else can help you. In the meantime, go ahead... turn as little as you need to in order to accomodate the larger floor.
I hope this helps.
Sincerely,
Jonathan Atkinson