I prefer J2 attacking.
In my game last night, I was Japan. J1 I split up my navy sending some ships down to sz36 and the majority of my navy to Caroline Islands with 2 trannies carrying 1inf/1art, 1inf/1tank, and the trannie in Caroline grabbing 1inf off of Palau. I took 4 territories in China including Yunan, and took FIC. I also flew extra planes and bomber down to Caroline. (If I remember right Caroline had 2 carriers each w/ 1fig 1 tac, 1 battleship, 2 destroyers, 1 sub, 1 cruiser, Islands had 1 bomber, 2 tac, 2 figs, 4inf, 1 art, 1 tank).
Settling on Caroline Islands that turn just really makes allies have to make choices. ANZAC sent their 3 ships to sz46 and landed 1inf on New Guinea.
The UK took Celebes and Java each w/ 1inf, left trannies undefended. Left Battleship, Destroyer, Cruiser at Malaya. He moved all his figs and his tac bomber to Shan State along with 3 infantry, moved ground units in India to Burma.
USA was like, “WTF”, and just moved all their navy to Hawaii along with 1inf and 1 tank, moved 1 bomber to Hawaii, moved 1 bomber to Queensland.
China attcked Yunan but couldn’t retake it and all attackers and defenders where killed. Japan held on.
Then J2 I blew up Hawaii navy and took islands, blew up all british ships, blew up ANZAC ships, blew up all British aircraft and units in SHan State, took Hong Kong, and reinforced Yunan. It was game over basically. In 3 turns I took Calcutta and USA never retook Hawaii (I added ships there thruought game)