Construction batallions for German, Rumanians and Finns all work the same way.
First thing, it's a patience thing, they will deploy slowly, and if HQ's don't move, it's better.
It depends on the command range of the HQ. So if they are in High commands they will repair far, if they are in corps HQ, they will repair up to 5 hexes. So corps HQ is not a good place for them, unless it's a dedicated corps HQ that you put on a railhead and leave there.
Best for Rumanians is in armies so they can repair further afield and not only in borders.
Best places for Germans is to have them in Army Groups or OKH and try to keep those HQ's further east.
The other thing is to use the German RHG HQ's as alternative FBD by giving them 4-5 construction batallions and parking them on railheads you want to repair.
< Message edited by joelmar -- 4/13/2020 4:14:01 PM >
"So much trouble in the world!" -Bob