In this article I shall give a rundown of the Soviet and German forces and the tactics they can employ. Panzergruppe Guderian' is an operational level game of the Battle of Smolensk, July 1941. The units are division sized, except for the German mechanised units, which are regiments.
Nobody knows the strength of the Soviet units until they are committed to combat.
The Soviets are much at the mercy of the leaders, who maintain the combat strengths and movement allowances of units within their leadership radius. Also, the mapsheet is covered in 16mm hexes not, as in some SPI games, by charts, comba results tables and the like. Your army should be centred on your nine Panzer divisions. The 18 powerful infantry divisions are also yours, together with a useful Air Interdiction capability. It is not really the quality or numbers of units that you are worried about, it is the time limit.