Why would germany even want to take ALL
the purple states in their first turn. Thats just plain stupid. It wears your infantry thin, and allow the Russians counter-attacks to be successful. And the purple states are only worth 1 IPC each, 0 IPC for the southern most purple territory. Germany should only focus on capturing Territories that have actual strategic value. On first turn as Germany, I would consider taking only Baltic States the first turn as Germany, So i could push more infantry to the eastern front, and fortify (Rumania, Poland and Baltic States).
And for Russia to build infantry in Leningrad, I believe is a mistake. If Russia spent all their money on infantry for Leningrad, I will automatically burst through Ukraine, and take Stalingrad. And if the Russians spend all their money on infantry in Stalingrad, I'll ignore Stalingrad for the time being and capture Leningrad. I would be able to achieve this because I built up equally strong forces in Rumania, and Poland + Baltic States. So I'd suggest building all your infantry in Moscow, and moving them into Belorussia (has huge strategic value for Russia).
Usually by Turn 2, Ill attack Leningrad head on with infantry from germany (via transport in baltic sea). And the Finland + Norway forces can help too. Tanks that were placed in Poland would attack, planes from certain areas. And lastely a few infantry at best. You might win, if you do that's great. Because next turn, Russia can't build in Leningrad, as they did not own the complex from the start of their turn.
In all, Moscow first turn, should make a Belorussian Stack, build a mixture of infantry and artillery (artillery for a counterattack into germany), and maybe 1 tank a turn (be sure to keep tanks in safe territories where they arent targets for German planes, so the tanks can blitz into attack when you need to). Build no planes or bombers what-so-ever, it's a waste of money Russia doesn't have. Let Britain and USA fly planes over, thats thre job.
Oh dear, I write too much