Better go with Nagato/Fuso.
The spread combined with the average dmg/shell makes it very hard to make good dmg with that ship with at lvl crew. Yes its fast, but huge too. Maybe with high lvl AA gunner its a thinkable option due to the good aa-platform but with crew below vl 95 better use nagato and fuso. Nagato may have equaly bad spread but better range, higher dmg/shell and a lot smaller hitbox. Fuso is smaller has a better punch und so is the funnier ship to lvl with.

B65 pierce better armour than Nagato Type 3, the gunset where everyone love using it.

Oh and b65 can take more hit than Nagato.

B65 is a nice platform for a player to use prior to reaching Yammy in order to learn the modality of using AA in battle, if they never had an AA-equipped ship.

Which is the case for IJN, since AA gunners get classed late, and the ship before yammy have poor T slots.

So before jumping on the yammy, if you got it I advise a few game on the B65.

Other than this its pretty useless.

I've found that, if you're competent with it, the Fuso is a far superior ship for leveling crew than either. Same crew as Nagato, similar speed, better spread and firepower, smaller hitbox, and more spare displacement. Plus, the bonus for attack against higher level ships more than makes up for the exp penalty for above-level crew.

B65 has decent range (for its level) and solid AA, but poor spread and a large hitbox. I've really found it not so hot without at least a BB4 crew, at which point you have no reason not to just run the Yamato. My main gripes with the Nagato are with the turret traverse, which feels limited and leaves playing the ship aggressively rather awkward (though not as bad as Ise). Relatively poor spread and small battery (only 8 guns) also makes it a bit difficult at-level, and by the time you're high enough to use it well, you're at the Yamato, which IS good at level.

Go with the Fuso until Yamato because with a higher lvled crew you can rush the BB5's and BB6's and wipe them out. Just wait until theres no scouts around or late in the game. I have done this before and it is very effective.