I love a J2 attack personally. I station bombers in Siam to strike any location the allied boats may try to hide. I also put a few boats down in that are like the caroline fleet to SZ 42, or just a destroyer or a carrier. It also lets you send a carrier or two to SZ 31 to threaten a Pearl strike on J2.
You have much better positioning on J2, with a proper J2 you can sink ALL UK boats and retake any DEI islands the UK takes. Along with that you can start your convoy raids on the UK, and you still get to initial kick on China and positioning J1/2. And you can threaten to hit Pearl with a large quantity of planes if you want, allowing you to either set the US back another turn or take Pearl heavy. On J3 you have all of DEI, china is hurt, and the US is the only power with a boat in the sea other than yourself.