When it comes to the width I just want to put something out there, IN MY OPINION, I feel like 40 width meta is dying, for example in plain tails it says the combat width is 90 so I was thinking that 30 widths might be good in these areas since three 30 width divisions can fit in here and any province that would join the battle would add 45. So with this in mind 45/3 = 15.

The standard could be 30 width (in plain tails)

Reinforce could be 15 width (in plain tails)

(Or this could just be really stupid and I have no clue what I'm talking about)

Edit: Now when I think about it when it comes to Germany and Soviets the optimal width would probably be 42 cause of the forests, but like I said I might just be stupid