I would play the IJN DD line and USN DD line ... for the sole purpose .... they are consistent and will teach you how to torpedo and knife fight.
You will learn to master your detection range, and you will learn to use torpedoes with IJN line.
With USN DD line you will learn how to cap contest and knife fight other DDs. Not to mention you will be providing team smoke (teamplay orianted).
So play them both at the same time.