Great work Shep!
I downloaded the latest version (5.x I think) and I have to say I really like your tech tree!
I especially like the increased supply costs of the more modern weapons, as the USSR these arty techs gave a nasty hit to my industrial output due to skyrocketing supply costs.
Only two things:
1. About the industry techs, don't you think that some boni are a bit off/not in relation to the costs? I researched Worker Efficiency I for 16 ics and 600+ days, which gives a (to me) meager 10% ic bonus, then Worker Efficiency II for 60 ics and about 200+ days, giving a 25% boost to my industry, all the way down to Worker Efficiency III which gives a 50% (!!!) ic bonus, as well as an Oil-Rubber Conversion rate of 1:3!
2. Germany AI begins rather on par with the Allies technologically, but instead of racing up the land doctrines and armor techs, it started producing an obscene amount of troops. By the end of 1940, they fielded about 200+ land divisions!

This seems to be a general trend with the AI, not worrying much about tech, but rather producing like mad.
Is this tweakable?
But complaints aside, this is a really great mod! Keep up the good work!