Help me pick a coal ship

I greatly enjoy playing the KM line, I have grinded to the Hindenburg, Schlieffen, and Bismark.

I have a 16pt. Lutjens, and do well consistently in Napoli. I mostly grind credits and freexp in operations. (I rarely play randoms)

The options I am currently considering are Agir, Pommern, Iwami, and Kearsarge

Agir and Pommern seem to be the most fun options.

I'm not too sure on Iwami as I only have a 6pt commander for the IJN, and the low secondary range with poor armor doesn't seem to be a good combo

I know Kearsarge is OP with plane spotting, and I do have a 13pt captain on my Iowa, but I never play CVs and the gun reload is L O N G

I would prefer a tier 9 since I don't have any credit printing ships.

Any help is appreciated