Well this isn’t exactly what I would call a safe Russian Strategy, however one way I found to defend it is through a live game I played this weekend. I played the allies with a 29 Bid that went to the Med in a stereotypical method. I purchased 3 AC R1 with US I pulled Hawaiian fleet back to San Fran and appeared to play passively allowing Japan to play aggressive towards the DEI and India, I was feigning a draw towards the Atlantic.
R2 I purchased fighters to fill the one empty AC, other 2 had been filled from mainland US and Hawaii, while staying in San Fran other cash just went to filler navy.
R3 I purchased 7 fighters and moved my fleet from San Fran to SZ4.
R4 I was able to fly all the aircraft from SZ4 to Yakuz in USSR and in R5 I had 7 US fighters and a tac in Moscow.
This might have been a one trick pony for my group, however it was very effective because keeping my navy in San Fran threatened the Germans as they thought I would swing around and let the Japanese be aggressive, however my move to SZ4 instead of moving to Hawaii or the Atlantic threw them off and effectively allowed the US to bolster Moscow with it’s airforce while at the same time UK was liberating Leningrad allowed the allies a decisive victory in Moscow and they surrendered afterwards seeing as the Japs had India but still needed Hawaii or Sydney and neither was feasible.
Hope that made sense, and works for others.