Well i did get across the river major in 1941 and did try and hold my gains, i had probably half of all German forces across the river trying to exploit my breach. The problem is your ORG continues to fall while the retreating soviet forces rises quickly while retreating, soon as there forces retreat back to other provinces he counters from 3 provinces beating anyforces i have there. I have had up to 100 divisions in the expolited province trying to hold, the attacks cannot be exploited due to the delay factor and the blitz option is no good when there are so many forces involde due to units attack different provinces at differnt times and being greatly outnumbered. So you do have to sit and wait a day or two and in that time you get countered and you cant retreat due o the delay, so you just have to sit and watch your army org and strength get smashed.
So if you build your army starting early in the game what is the cost of supplying so many forces for the first 2 years, plus then upgrading all thoses forces to 1941 technoloiges infantry and tanks.
Omni i have used totaly Heavy tanks, Self propelled artillery, Tank destroyers on all my tanks and motorised divisions before only to get smashed at the river line. In that game i had no navy at all, it was the largest most advanced army you could possibly get as Germany. But becuase i didnt have enough enigneers trying to cross the rivers was impossible, i think my tanks just sank in the river. To breach the russian river lines you need lots of engineers on your shock troops so about 50-60 brigades to attack normaly 30+ russian divisions camped behind the river.
Each marine Division costs 118 IC more then a standard infantry division plus takes 54 days longer to build. With this amount of time to build them you can only get 12 built in 1 serial build by war and thats if you have the tech from Jan 1st 1936 which you dont. So it will take two serial builds to get you to around 24 by 1941 and for those troops to be anygood will also rbe rquired to be upgraded before russia, plus the extra cost of any brigades attached.
Each mountain division cost 1.7 IC more and takes and extra 30 days to build then normal infantry. With a serial build you can get around 15 divisions built from Jan 1st 1936 until Sept 39. So in order to get about 60 divisions built for a good offensive force you will need 4 serial builds.
So all up to get a good river offensive forces of 24 maraines & 60 Mountain troops you need two serial builds of marines and 4 of moutain troops.
Now here comes the interesting part. To build just these shock troops will require about 45 IC out of your 95 aviable at the start of the game so nearly 50% just to build your shock troops. Now to get 50-60 armour as major would like to try. If you start building tanks from the start of the game lvl II medium tanks as these are the easist to upgrade later. Each tank costs 16.6 IC and takes 167 days to build, so you can get 8 out from 1 serial build by sept 1939. So with the remaining 50 IC spare you can do 3 serial builds and have 24 tanks by sept 39. And thats it you have no more IC to build anything now. No airforce at all, no more HQs, no spare IC to upgrade, this dosnt take into account all the extra supply costs which are imense once you get going and will probably chew up most of the IC gains done through techs and gains through Austria and the Checks.
You could drop 1 tank serial build this gives you another 16.6 IC to build say one serial run of interceptors at a cost of 11.4 IC you could also build 1 serial run of infantry.
So by war you are going to have 24 marines, 60 moutain troops, 21 tanks, about 36 infatry from your starting army. Your airforce will consist of 12 outdated interceptors and your 8 starting tac bombers which are useless. All these forces are 1936 tech or worse. You dont have any IC or very little for upgrades. So now that your at war you have got 687 days before war with the USSR. You have a crap airforce, no navy and a heavily outdated army. It will take 1 year to upgrade everything to 1939 Tech at lest maybe longer. To also build more forces which you will need, you only have 24 tanks you need twice this for russia if you dont plan on using motorised divsisions. So how do we build another 24 tanks in 687 days? lets have a look.
In this time we can get 6 tanks built with each serial build all lvl III tanks costing 16.6 IC at this stage of the game. To get another 24 tanks will mean 4 serial builds costing 66 IC. This is about 1/3 of your IC after you conquer france, poland, low countries, norway, sweden and so on. Now you are going to need more infantry you need to cover the west and enough forces to at lest cover the russian front if not on the border then a few provinces back. So you want a minium of 120 plain infantry at present you would have about 50 all 36 and some 1918 infantry, so we need another 70 odd. 6 serial builds will gives us just over 70 new infantry 1939 standard by war with russia so thats another 30 IC gone. Hang on we have spent over half of our free IC and no upgrades, no planes, no brigades where is the IC and most importantly TIME going to come from for all these forces.
Put it simply it cannot be done. This is only a glimpse of the complexity and considerations you have to take into account to build a force capable of fighting the USSR let alone winning. The cost of building this army early is imense and upgrading latter will kill you, if you don upgrade you will have no chance against a full tech Russian army that out numbers and out techs your forces. If you dont build it starting from early in the game you will never get all the forces you need. Plus with the starting forces you have and there Tech level i would be confident as a UK player i could stop you on the french border with all 39 tech units from the UK and France. with our new game you will also have to consider war can start anytime and cannot rely on all this time to build, you could be caught short.
So to put it simply good luck, you will need it an pray.