Noll:
All Italy needs are 14-20 IPC sent to Russia. We’re really only talking about 3-5 Infantry and a Tank to pop a territory closer to Moscow and allow the Germans to reinforce it. That gives Germany the OPTION to move their aircraft over to defend as well. I say OPTION because Germany also has the OPTION to leave them in range of any British fleet that might suddenly appear.
Other than an initial investment for a carrier, Germany is sending all of their resources at Russia. I am not holding anything back. (Planes can zoom over as soon as they are needed, so leaving them behind in W. Germany is not really holding them back.) Italy is working on Africa and then once England can actually do anything to Europe, reinforcing France to stop them.
America, as we have already outlined, is useless until Round 6 at the absolute earliest and are the easiest to slow down if you wanted too. (Because England cannot open the route for them, so a destroyer WILL block America where as it might not block England.) If you really wanted too. I do not think you do, but if you do, you can.
As for submarines, if you are going that route, you need 4 submarines total. You start with 5, so this should not be an impossibility. You want 3 or 4 in SZ 109, 1 in SZ 106 and if you went 3 in SZ 109, the the last one can go off the gold coast of Africa in that convoy zone. Will they be killed? Eventually. But that’s not something to worry about for quite some time, at least 3 or 4 rounds, probably 6 or 7 rounds and at that point, you’re already in position to start three hitting the Russians in Moscow.