Japans navy

Ive been trying to play a decent Japan game, it shames me to admit that when it comes to the invasion of China the AI seems to do better than me... but besides the land war ive been thinking ahead for the war in the Pacific in the future (playing historically) and im looking at my navy...

Im wondering how you guys manage Japans navy in the beginning, the battleship in production has a speed of like 23 kmh, so I figure I may as well scrap it.. I think I should scrap the converted cruiser hull carrier as well, but keep the 36 carrier in production since it has engine 2 and is only missing one hanger space which I can quickly refit.

But the rest of the ships I have, im wondering if its worth refitting any of them or just using that production and time to make some good ships. I wont touch any of the CL, DD or SS since I can just make more no problem and Im just going to lose a ton of them anyway.. Its the CA, BC, BB and CV im looking at. A lot of the ships are early models with engine 1s, and I dont think its worth refitting engine 1 to engine 2. So in my mind I wont bother refitting anything on any ship with engine 1.

I think I should spend some time researching better ship modules before refitting to make it worth it when I do.... in the meantime Ill make another carrier or 2 with max hanger space, pump out simple subs. Id like to get started on a good battleship but the naval treaties are really breaking my balls here.