User blog comment:Homuhomu123/Trigger Rates & Effectiveness of Anti-Air Cut-In (AACI)/@comment-25335190-20151115084258/@comment-26316660-20151115095957

If you want to focus on AA, use 2x 90mm HA (*10) + FuMO25 + 25mm AACD. That's the most optimal for you, I would say. T21 Air Radar Kai (*10) is nice, but has limited use aside from AACI purpose, so I personally think not worth ur precious screws.

But I still prefer having more firepower since her K2 yasen power still better than most non-K2 CA like Takao & Atago, even Kinugasa K2.