For global it depends on what round you are attacking. Like for Germany you pretty much go all mech and armor to attack on G6. Otherwise you do round 2 strait arty then you attack Russia on G7 (buying mech/armor for the other rounds).
That is pretty much it. Like other units simply do not make it in time. Like your entire german force collides on russia at a specific round. You only need to hold germany, everything else lost can be reclaimed after russia falls including france, I mean you should be using Italy to defend anyway, it has nothing better to do.
If you do a more economic style of play then you probably invested into the middle east and a more defensive style. So yes then you have a more mixed buy going on.
Global is a freaking long game to play income style with, just win, it is faster.