I’ll only go after Hawaii if the UK or Russia hasn’t landed any planes in range of the Sea of Japan. If that condition has been satisfied I’ll attack the Hawaii Seazone with 2 bb’s, carrier, bomber, fighter, submarine and attack Hawaii with 2 infantry and a fighter. I suppose if you are really feeling aggressive you could hold the sub out of the combat and on non-combat move it off the coast of Mexico to block the US Pacific Fleet…but I never do this…too risky if the dice go bad at Pearl.
Such a move gives Japan some options and places pressure on the USA. USA must now defend Western USA from a possible attack…giving Germany a bit extra time. The optimal move on J2 is to take Australia from there you can hit New Zealand and take the Jap fleet into the Atlantic, take Brazil and put some more pressure on them USA guys.