I once played v2.0 with, custom settings, where after autumn 1941 every motorised unit suffered 4 fuel loss/per turn. This gave that effect, what the Germans suffered probably, but with that effect, the game become really hard. The only chance is to capture the Caucasus very-very fast. I could make it, after several tries, but "Do not try this at home, kids!"
I use the Elephant N of Voronezh W of the bridge. With heavy air protection and in the winter with arty support too. In that way, it is possible to avoid strenght loss (although I had still reload several times, when I thought it is enough defended, but it was not enough...) and the vehicle could be used as it's best.
Plymouth is not a major hex anymore, volks in v2.0.
So probably the best way if you want the invason 42+ on to attack from the North. I could do this with the Stalingrad save, but with the Kursk save you cannot be fast enough to avoid d-day. When we start from the beginning, I think the best methode is still to try the invasion in the winter of 41, probably from S-SW.
