Aaah those are the numerals you were talking about.
Also, if you know when a certain piece of technology came out, or what components made it up then you can get a "unit" or type of unit that you like and use that.
I.e: for Germany, I know that if I research Heavy Tank Cannon 8.8cm L/51 and its other techs up to that level I will get the Tiger. But that is just if you like using certain types of units.
Also note that, even if you have level III, IV or V units going up against I, II or III units, yours won't always come out on top. This is especially true in naval and air combat where the doctrines play a HUGE role in how your units fare.
Some essential doctrine techs for land are: (in my opinion) Spearhead, Grand Battle Plan, Overwhelming Firepower (gives 5 brigades to a div.) and one that shortens time between attacks and raises supply throughput.
If you have any more questions, just post
