Board Thread:Questions and Answers/@comment-171.232.158.0-20150920031836/@comment-26486243-20151028071208

Support expeditions can use 46cm or 41cm guns on Kongou-classes as well, as overweight mechanics do not apply; since they give more firepower than Proto-35.6, use them instead and carry more radars. On the other hand, past 4*, plain 35.6 is already better than Proto-35.6 in normal sorties.

Basically Proto-35.6's used by new admirals without access to Akashi yet. Never upgrade 35.6 to Proto, it's a trap.

38cm kai is far and away the best, but you don't 'need' them for firepower cap in the day, so their main advantage is in yasen. The four 38cm kais you get from a single Bismarck, I'd recommend upgrading all of them and using them whenever you can. But instead of grinding multiple Bismarcks, fill the rest of the slots with upgraded 35.6, and use the reso on something else instead that actually helps more... like extra Maruyus.