Thing to consider:
Oil efficiency isn't my priority.
12-4 is easy to clear with level 120 ships, if your ships are around level 100, 12-1 could be a better option.
UR gear isn't necessary, I use it because I have it.
Mob Fleet:
For vanguard we can use any ship, In my case I'm leveling those up. If you want to save some oil, you can use Isuzu (Retrofit) for anti air or even Cassin (Retrofit) / Downes (Retrofit).
For Main we need Eagle Union ships, in my case I choose those so I can synchronize their attacks, hopefully reducing the clear time for each battle.
Langley's skill 'First-Generation Carrier' will boost your exp gain, but only works on carriers.
Boss Fleet:
Cross fleet buffs, heals, ACV for air supremacy, etc.
0:00 - Mob Fleet
5:24 - Boss Fleet
6:50 - Equipment
#azurlane