Tigertank:
Purchase all inf and keep counterattacking the Germans in force, but do not go too far into Germany to put yourself in range of large forces of German tanks. For example, on your first turn, bring in 3 inf from Archangel, 3 inf from Russia, art from Russia, 2 tanks from Russia, ftr from Karelia and ftr from Russia and attack West Russia. You should be able to wipe them out and have a strong force remaining. On noncombat, move 2 inf from Kazakh to Caucasus, land both ftrs in Caucasus, move tank from Archangel to Russia, move 2 inf from Novosibirsk and 2 inf from Eventl National Okrug to Russia, move 1 inf from Buryatia and Soviet Far East to Yakut (leave only 1 inf in each coastal territory - their only worth 1 IPC each and not worth losing a lot of units for). Also move sub to sea zone 6 to blockade the German navy in the Atlantic. With the 8 inf you purchased, put 4 in Caucasus and 4 in Russia. Archangel will be empty, but Germany can’t get to it anyway because you took West Russia. He may take Karelia, but that’s not that big of a deal. UK can invade and take over Norway on it’s first turn, putting those German forces in Karelia between 2 forces. Just beware large stacks of tanks coming out of Germany. Keep using small counterattacks with inf. and the 2 ftrs (try to keep your tanks around as long as possible) which slows down their tanks and prevents concentrated attacks on Moscow or Caucasus. These forces should be just big enough to win and that’s it. Keep your larger forces in reserve for defense or counter attacks. You want to avoid a big showdown of your inf vs. his tanks at all costs because you will be crushed. I was able to stay strong with Russia doing this while simulataneously fighting Germany and Japan.