You could always set a standard amount for the units (total number of men throughout the war for each nation, divided among the respective pieces and averaged out to assign a static number of “man power” per piece).
Then just change the number of pieces on the board until they match “historical” numbers in terms of placement and troop strength for Spring of 1942.
As for finances, perhaps even the cost of pieces could be changed.
But I’m just throwing out ideas here and if I have the time maybe I can get around to doing a project like this (shouldn’t take more than a couple of hours to figure a(n) “manpower” per nation, but several more hours to assign pieces to the board to reflect those numbers accurately).