There is not a single US unit, aside from the transport at Pearl, that you can hit J1 that you would be unable to strike J2.
With proper positioning of your fleet, there is no where for the UK fleet to hide from a J2 strike either, other than perhaps SZ 59, and if they go after the indies you can smash there transports anyway.
What is with this obsession with a J1 attack, it is about as brilliant as the all armor for G buys that were unbeatable, for about a week. The war rules encourage a cat and mouse game, where the allies and japan try to draw each other into attacking by exposing valuable units. A J1 attack will end in axis defeat once the allies know how to play.