User blog comment:Shinhwalee/Major Event Preparation Guide for Admirals/@comment-1365426-20151110102302/@comment-24930367-20151110103729

Maya's AA cut-in triggers from 25mm AA Gun Concentrated + any high-angle gun (+ air radar) setup.

Since 90mm is the only high-angle secondary gun you can improve at Akashi, it automatically becomes the best choice for Maya.

Assuming you still want a seaplane, then it would be 20.3cm + 90mm + 25mm AA gun + seaplane; 25% weaker AA cut-in for half-assed daytime cut-in.