Looks to me if you can keep pressing the line will break badly. 5 million men is about average for Blizzard.
Generally when I have a bad winter it for me falls apart in early january.
Once you pick off a few Divisions thing fall apart quickly.
Also the main issue for you is building your morale and droping his.
I'm not sure you tried entrenching in the newest patch. This time it really can work, IMHO - and even forts lvl 2 are sometimes enough (I can squash them, but it is a major effort; level 3 would be very tough). As you know we are playing a few turns in advance and as soon as I get a new turn from Mike, I will post next two weeks...
The issue is that for my prepared attack to be successful I need more or less 2.5:1 in initial (on map) CV in December (so taking into account display doubling of my CV it is 1.2:1), 2.5-3:1 or more in January and at least 3:1 in February (preferably 4:1, so 2:1 after factoring the 2x display cv increase)). After 2-3 failed attack, the very well refit division needs to be sent to refit again- as such I need as few of those as possible - and I was way too optimistic in the first two turns about the odds, and sappers reducing forts. As such, in the first two turns I got ratio of about 60-70% success in attack. Too little to have the offensive sustainable. Afterwards I use more forces, it got better, but still, it was difficult to keep divisions in strength (i.e. above 8000 guys - below that the division is not combat worthy anymore), having few digging armies and preparing reserves for the march snow.
Also, there are three more issues which made the blizzard more difficult for me:
(1) the support units which can be stronger than the division I attack itself (happened to me many times during this blizzard, attacking division of cv 40 in the battle screen, and getting pioneers of cv 50; total of SU equal to cv of division happened maybe 10-20% of time),
(2) armored reserve (kills pretty much any attack, Mike is very good at setting it and it took me much thought to go around that) and,
(3) the inability of my sappers to remove forts... It has not happened to me in the whole blizzard that my sappers removed fort level during a failed attack. The attack either works, or not... If it works, it is hard to say whether the fort was removed by sappers or not - when it doesn't - well the fort *always* stayed the same level.
The reduction in German cv due to failed checks happened relatively little to me. I would say, the chance my cv will be divided by 4, contrary to the usual 2 is perhaps bigger than the chance the German CV will be crippled. It can be divided by 2 due to bad supply, ammo issues etc, especially if I bomb the unit before and get it fatigued and into 'red' supply status [in the unit corner, soft factor] (or is in red supply) but I found dividing cv due to blizzard as relatively rare. I asked Mike about that and he said that he upgraded his leaders to the best possible and that he spent majority of AP on those. Maybe that is the reason. Again, I did the calculations and it seems to me that for average check, the chance of failure for German is maybe 15% - as Mike upgraded leaders that probably fell to maybe 10%. As in my understanding 2 checks are made, this means that the reduction due to blizzard happen maybe in 1-0.9x0.9 - around 20% cases - way too rare to rely on it.
Anyway, I will keep on reporting so you can see the progress... I am really keen to see how things will unwind in '42, but I expect it to be a very, very tough year.