Board Thread:General Discussion/@comment-30404167-20161211060312/@comment-25149401-20161211122004

Even for 100-slot ttks, it's always good practice to keep 1 copy of non-trophy ships. Use your own judgment because waifu > stats/efficiency.

All of the 4 kongou sisters is important for the 4th fleet. While fbb is usually needed for routing in events (shiplocks), it is also amazing for general use. Also, there are only 4fbbs that are easily accessible, others are event drops / bisky lsc). Otherwise, I'd prioritise hiei and kirishima  as they have the best stats.

Ise-class is the most economical bb (but not as good as compared). They are most used in lower levels as a bbv substitute for fusou-class, as well as for efficient grinding purposes (2-4,3-2,4-3). You can arguably keep just 1 copy of ise or hyuga if needed, but not essential until you plan to do the catapult quest chain (which I assume you aren't anywhere close yet).

Mikuma can be converted into a CAV when kai, and is the rarest (dropped) CAV, as she also has a 20.3/3 in kai stock. I'd suggest you keep one copy of every cav for shiplock purposes, as there are only 6 ships of CAV class.