I also did some ranked battles over the weekend. By lucky coincidence I'm currently at Nagato, Myoko, Gneisenau and Kiev in my various tech tree grinds, so I have plenty of T7 ships to choose from.
Unfortunately, it turns out I suck in Nagato (which is sad, because I know she can be a terrifying ship). Initially I went with the secondary-buff build, but since T7 is currently swamped with Gneisenaus/Scharnhorsts, there's rarely an opportunity to brawl. So I switched to the accuracy module to increase my oomph at long range which seems to help a bit.
But still, after the shotgun-drive-by-fun-tiems in Fuso, I'm struggling a bit on how to properly use Nagato (also being told so by 133t cl4n playorz in the chat).
Should she be played more like a bigger badder Kongo?
In the meantime I'm doing my heroic ranked deeds with Myoko... much burn, such love.