I realize the answer to this question is highly subjective, not standard, and open to a range of interpretations.
I'm interested in anyone's answer; be it a hunch, a WAG (wild a$$ guess), an advanced mathematicallys (MATHS) derived formula, or your direct experience from having commanded a fleet of starships.
So, without further ado, how long do you imagine, in real-time, does the naval space battle represented by a 6 round engagement of Armada take?