Board Thread:Fleet's Prepared-ness/@comment-24590359-20150805194914/@comment-26289480-20150806062216

You need S drop for Hiryuu. And the chance of getting Hiryuu at 2-3 is very low anyway.

You can use 2CLT 1BB (slow) 1 BB (fast) 2CV to farm 2-5. this is cheaper and easier (possibly because of open tropedo strike)

You could just use my guide  on how to grind 3-2A rather than work it out yourself.

http://kancolle.wikia.com/wiki/Thread:290345

And If you want to maximize your opening strike damage, Ryuseei Kai is much better than 12A.

Anyway good luck for the event.