I would say at first that Germany was much stronger because of the amount of tanks and the lack of UK and USA support for the Soviets . Now I think is it even . Last two times I played the Allies I invoked the “Shell Germany back to the stone age method”. All the Allies (USA and UK) need to do is build all destroyers and a few transports that will carry one tank each. I would just beach land on Germany with one just one transport carrying just one tank and bombard with as many destroyers as possible. By round 5 I had UK shelling the Germans with 7 destroyers and just one tank. I did the same with the USA. The reason why this works is in a bombard your destroyers will shoot only once at a 2 for cover support and the one tank that costs only 5 ipcs will fire at a 3. Now this is where Germany gets screwed because they can only kill the tank. So in that battle the Allies will only loose one tank while the Germans will lose more (simple economics). This is a good tactic for two reasons one being the simple number losses for the Germans and two and equally as important is that is forces Germany to buy infantry to defend Germany rather then the speedy tanks that attack at a 3 and can be used to aid the down fall of the Soviets. Keep doing this and keep adding destroyers to the attacking group. USA will need at least 3 transports and the UK will need two transports to provide a constant stream of one transport carrying one tank to the German coast.
Now the Soviets can’t run and hide they must attack the German tanks at the right time. Which is when they are defending at a 2 and don’t have allot of infantry that can used for fodder. This is a common tactic with A&A. So the battle between the Soviets and the Germans boils down to who can kill whose tank force first.
The only thing else I can think of is use your 12 ipc at the beginning to match what ever the Germans do. Just to play it safe.
Ultimately its the random rolls of the dice that decides who wins the battle. All you can do is play the percentages.
Hope this helps