Bruce, I did indeed ask for comments, thank you very much for yours
You are correct that the question of German resource distribution arose from the German decision to fight on two fronts, or even three fronts, if the Mediterranean is to be considered a distinct front. What I did not have the space to discuss in my study, limited as it was by maximum word count, is that Germany did not have an effective option for continuing the war other than attacking the USSR. The objective of Operation Barbarossa was German domination of the European hinterland and use of the associated natural resource base for the German war economy. The Nazi regime was aware that the attempt to crush British resistance had failed and that the United States could enter the war in the future, so Germany needed resources to continue the war with reasonable chances of victory. Otherwise, the German war effort would simply wither on the vine, suffocated by the Royal Navy blockade. Given the experience of the First World War, Germany's entire strategy was geared to avoid such a turn of events.
It was Britain, and ultimately the United States as well, who exercised the choice to either not become involved in the Soviet-German war, and then to fight a long war against a strengthened Germany, or to aid the USSR with the aim of preventing German domination of all of Europe. Churchill took the responsibility of making the decision to aid the USSR, aware of the consequences: "If Hitler invaded hell I would make at least a favourable reference to the devil in the House". This aid effort eventually proved overzealous, as German domination of all of Europe was replaced with Soviet domination of half of the continent. One of the objectives of my study is to demonstrate by implication that, since Western air power was quite effective in defeating the Luftwaffe, better strategic choices could have been made during the war.
Kind regards,
Dan