I didn’t read it all, but as germany, what you wanna do is make a superstack and scirmish, same as USSr.
infantery is the MOST offensive unit of the game, while tanks are the most DEFENSIVE unit of the game.
Think about it, a good opponent will never alowe you to hit his stack and win the game, so to be able to advance, you need to be strong enough to move next to your opponents big stack, then he will retreat to his reinforcements, and you need to build enough infantry to be able to stand next to him again.
In essence, to be able to take new terretories, you need to have enough infantry to actually be able to hold it against counterattacks.
tanks on the other hand is a GREAT defencive weapon. Imagine russia with 20 tanks (+10 inf) in moscow, 15 inf in cauc and 50 inf in w russia.
at this point, the german is not able to stack next to cauc because you have too much of a punch there, if you are lucky, the japanese need to have about 30 tanks to be able to stand in persia, (which means you can get the tank+ inf stacks in africa to russian homeland). and if japan is to advance to nonsibirsk, then you have a good counterattack there. in fact it does not matter if your tanks are in moscow, w russia or cauc, from all those terrs they can prevent the axis from holding any of the most important terretories on the map. the tanks are not there to advance and take berlin, but to prevent the axis to stack in one of the teretories next to your most important ones, thereby forcing you to chose which one to hold.
so, tanks are defencive, inf are agressive units.
artillery is not as good.
we have similar examples for germany, if germany have 30 tanks in e/europe, then it is more or less impossible for the allied to land safe, there will always be a counterattack strong enough to wipe the allied landingparty off the map. Germanys main need for inf is to keep berlin, scirmish and keep the tanks safe. (we assume the allies are able to stop germans from ever having a real shot at cauc).
The great strength of tanks is NOT their stats, but their MOVEMENT. and infantry standing in moscow can only reach 6 other terretories, while a tank standing in moscow can reach 12 terretories, which means that any axis stack in any of those terretories has to be strong enough to withstand the tankstack in moscow.
when I build units with ussr, I build (after round 2) about 5-8 inf / tank I build 0 artys. with japan, I try to mix inf/tanks, with more inf early and swich to tank only when inf no longer will reach important battles in time (assuming I built ICs).
with USA I try to buildabout 6 inf 1 tank 1 art per 3 transports. with UK I more or less mix according to the on map situation.