Which would be your preferred lines of advance on German T1, and which are the key depot candidate cities and towns to reach early?
FBD4(AGN): Raseiniai, Jelgava, Riga? Or just have Riga act as a main import port in the north... is that enough for AGN in the beginning? Is it worth to build depots south of Riga? You can get Raseiniai online on T2, but is it really useful? Should FBD4 perhaps concentrate on getting the Vilnius - Pskov double rail line online to allow two FBDs operate in AGS area?
FBD2 (AGC): This FBD can be diverted to either northern approach (Vilnius-Daugavapils), or handle Vilnius-Minsk supply to allow two FBD in south?
FBD3 (AGC): Brest-Litovsk => Kowel => Rovno => Zhitomir? Or maybe double with FBD1 toward Vinnitsa? Or even more south if sending FBD1 to Romania is still a thing?
FBD1 (AGS): Lvov-Proskurov-Vinnitsa => link with Romanian FBD toward Odessa? Can you still send this south to Romania to get quickly to Odessa?
These are just my random musings, and are based on WitE1 experience. FBD depot boost makes everything probably even more complicated? Also I'm not sure how effectively port supply works, take Riga for example. You can probably boost it to work on quite high capacity with AGN HQ stationed there?
I liked to micromanage (indirectly) my support RR battalions in WitE1, and it seems to work still! How risky would it be to remove RAD/OT battalions from FBDs to act as pin-point repair units on Corps/Army HQs? I noticed that I could leave only 3 road construction battalions for FBD4, and it could still operate at full efficiency with some repair margin left at RRV5 (RRV4 is still 1MP/hex). Doing this I received three support battalions that each repair 1 hex per turn. Problem here is that they can't be returned to the FBD which makes it vulnerable to attrition and probably bad weather later on in the campaign.
Depot placement is a big mystery for me still since I haven't had time to play around with that yet. You probably don't want to spend too many APs spitting these out, but at least for now it's still really difficult for me to figure the exact spacing and capacity of the depots that I should have. AI assist places "up to 10 depots" with a max cost of 5AP, that seems like AI depot assist could be even more efficient than placing them manually?