I was wondering why not just go INFx2 ARTx1 ATx1
The only real point where this even will be an issue is Barbarossa. Its generally considered you do not need that many AT brigades. Plus I would have as many or close to as Armor Divisions as the Soviets by the time I launch it, so with the AT units, I would be fine. Generally my Divisions have 3 INF/ART and 2 INF/AT, most players now would only use 1 AT per Corps, so actually I have more. Also although not in this tutorial I have lately begun swapping TD for Spart in my Armor units.