I picked the first option (buy mostly inf/art) and the last option (move siberian troops west). Those seem to usually work best for Russia.
However, I have to admit, I’ve tried a number of strategies with Russia and none seem to work. Unless the Brits and/or USA do a lot in the West to disturb Germany, I’ve found that Moscow just about always falls. Once that happens, it is usually an Axis victory, but not always. Sometimes the USA and Britain are strong enough that they overcome Germany even with Moscow falling.
I’ve tried putting heavy defense on the border. Once Germany breaks through it, even at a high cost, Russia doesn’t have much in reserve and Germany seems to be able to produce more and take them out.
I’ve tried setting up a strong reserve for counter-attack. Usually, Germany attacks Russia with four main groups: Finland > Karelia, Poland > Baltic States, Slovakia/Hungary > E. Poland, and Romania > Bessarabia. While Russia is ususally somewhat successful, meaning they might wipe out 2 of the 4 groups and even whittle down a 3rd, it also costs the Russian a LOT of units and they are often left with just a few tanks having lost all lesser units in the battles. It sets Germany back some, but they seem better able to send more units, usually armor and mechs, to wipe out the Russian tanks and push on. Meanwhile, Russia is severly depleted with a lot of open territory for Germany to gobble up.
One other tactic I’ve tried with Russia is continuous purchases of infantry. Put some in the Leningrad,Stalingrad and Ukraine factories so Germany has to fight some for them. Put at least 1 infantry in each other territory to keep Germany from blitzing and slow them down some. All the rest put in Moscow and let them pile up. By the time Germany gets to Moscow, there is a ton of men there. Only problem with that is Germany will surround Moscow and keep building new units in the Russian factories. The German force keeps building while Russia is not making much money because Germany has most of it’s territory. Furthermore, German bombers can now bomb the Moscow IC at will, costing Russia more to repair the damage and leaving them less money for more defensive units. It may take an extra 2-3 rounds, but eventually Moscow will fall.
Basically, I just don’t see any way that Moscow doesn’t eventually fall to Germany. Unless Germany really screws up somewhere and Russia is allowed to go offensive. Or if USA/UK somehow takes away some of Germany’s income so that Russia gets back close to even.