About the IPC values, I have some new ideas.
Now Harrison’s book have the GDP (gross domestic production) numbers for each country during the war. In my idea, a nation may only use the GDP from its home territories. The GDP from conqured enemies are useless, because you cant put an enemy population into good use. But you can use the resources from from an occupied territory. And this is in fact what happened during the war. Of course not every territory got any value now, only the territories with big time resources like oil and iron ore got values, and the home territories.
Lets take Germany as an example. Germany homeland got 12 IPC, because this is the historic GDP of this country. Germany historic got 50 % of its iron ore from Sweden, so lets give Northern Norway (Nordland territory) 4 IPC, and Germany got 70 % of its nickel from mines in Northern Finland, so lets give Lappland territory 4 IPC. Also Germany got 90 % of its oil from Ploesti fields in Rumenia, so lets give Rumenia 4 IPC. Now the other countries have no IPC value, they are worthless. If Germany conquer Balo-Russia, it gets no IPC gain, but if Germany conquer Caucasus it get 6 IPC from the Baku oil-fields. Can you dig it ?