I don't think so, the retreating line is near-or-enough the same length as the Southern Vistula line. And the line is only used if the troops get up there in the first place. But I guess the low infrastructure provinces in the east would need less troops (if thats how infrastructure works).Hopefuly this retreat will shorten the front enough to allow you to free up troops to assist in the north.
There is no hope then. The new line isn't supposed to be an offensive, just to stop the Germans from easily flanking us.Retreat enables the Wehrmacht to concentrate even more and the Luftwaffe will still be a pain. Even if you stack your new front with 5-6 units each, it'll hardly be enough. Your only hope are, god forbid, the French.
I don't think Yugoslavia will be very tough for the Germans. And the Brits aren't doing much at the moment.Well the majority of the Wehrmacht that took out Hungary may have to inturn turn around and help take out Yugoslavia, and we cant forget about the British advance along the north of the Maginot line, if they are still advancing
Update in 5.