User blog comment:KptRudobrody/Akashi guide for everyone/@comment-26337865-20150916145200/@comment-26337865-20150916155616

Regarding the 12.7cm gun and the 20.3cm gun, I still think it's worth mentioning them as viable options to improve because of the ease of improving them. My current plan to improve medium guns is to get 2x 20.3cm no.3, 4x 20.3cm no.2 and 2x 20.3cm guns to max. That way I have good guns (20.3cm +10) available in the short term, while leaving the no.3 and no.2 variants as long term projects.

"If there is other formula would you like to share it with me? I would like to include it for sake of more data in one place." From the same Himeuta thread you linked, the most recent post by Jifaru states that the night battle bonus is sqrt(n) for both medium and heavy guns, where n = no. of improvements.

Regarding torpedoes: My personal theory is that torpedoes do not gain additional accuracy upon improvement, but rather gain additional 'torpedo accuracy', which is a hidden stat separate from accuracy. I have nothing to back up my claim though, because I cbf testing for torpedo hit rates, which is much harder to test than regular shelling. It has the potential to serve as a hypothesis if someone is motivated to test it though. For now, I would say that it is unknown whether improvements to torpedoes give additional accuracy, since I've lost the source that says they have no additional accuracy.