The easiest way to balance the game is by moving one American IPC bonus from US to Philippines for every Allied win and withdraw one IPC bonus from the Philippines back to US.
Our group of players balanced the game with 7-9 moved American bonuses on the Philippines.
Later…
Alpha+ (about 6-8 months ago) was really broken, when Germany hade about 85%+ chance to take London in turn 3. We gave up Alpha+ and plays today with original setup and Alpha+ modified bonuses.
Extra German bonus in France. 5 IPC.
Reduced Japan bonus not declaring war. 5 IPC, meaning Japan loose 3 ICP if they take France Indochina. All depends on the Japanese strategy if they take FI or not.