From: Utlima Thule
Some quick notes on this, all this is in the manual.
The building blocks are:
1 - Chassis (ie the frames for AFVs and planes) use arms pts in their production (and all are capped in their per-turn production). Over the game the actual model made from a core chassis will vary according to how it is actually fitted out.
2 - the stuff that makes it useable (guns, engines etc) uses supply (ie off HI), this stage is in theory relatively unconstrained but of course you need the chassis first
3 - the rest uses arms pts (so that is anything from artillery to small arms)
4 - but in reality you can ignore HI and Arms Pts in #2, they are a tool to a purpose but no where near the importance they have in #1, as:
5 - most of the generic stuff is built to need but also to a cap (see 28.2.3 of the rules). That cap matters more than anything else as you can't exceed it (they will change over the game - you can find this sort of stuff in the editor)
6 - there is some stuff that is genuinely produced to need but its the sort of small scale weaponry you find in a typical infantry element
7 - in practice? You'll find that both economies are less under your control. I personally think this is good, you are the OKH or Stavka, not Hitler or Stalin
8 - so the Soviet player can indeed build more flexibly but that is a bit of an illusion. You can order as many heavy artillery SUs as you want (up to around 250 if I recall), but you are not going to get them fitted out and on the map (due to the caps)
9 - so given all this, the game design effectively removes all the sub-game around factory evacuation that has become such a feature of WiTE1 play
10 - also in #2 rail cap is local not universal, so the evacuating factories do indeed claim rail cap but its less visible to the player as its more localised
This leads to the role of HI/Supply production in #2. Again in #1 this is mostly a global issue with some localised delivery challenges but the key to the Soviet economic planning is retain enough HI to supply all your needs.
You'll find in #2 that this is a bit of a non-issue but that delivery to location is the real challenge. This is not just in-unit supply its also the supply taken building depots, expanding airfields (esp to size 2 or more) and fortifications > 1. These 3 can be supply demanding and hard to do in poorly supplied regions (here they will be slow due to delivery of supply and/or really cost your combat units supply). So its not really about HI its about depots, rail capacity and delivery. As an eg, you can expand an airbase from 2-3 in a turn if its on or next to a NSS, it can still be doing this in 1945 if the target hex is off on the edge of the supply grid.