A while ago I found some papers written by the then-Soviet Army Studies Officer (now the Foreign Military Studies Office) during the late 1980s. They really provide a view of the late Cold War Soviet Army different from the sterotypical inflexible Red Horde thought of when one thinks of a Soviet offensive and should be applicable for the game.
Soviet Non-Linear Combat
I asked one former intelligence guy about this paper and he replied that the Soviets were anticipating non-linear combat long before we recognized that they were. In a mid to late '80s conflict like he said the he would expect the better-trained Soviet units to be able to carry out those sort of concepts.
Heavy Opposing Force (OPFOR) Tactical Handbook
It's a manual for opposing force training published in 1994, but my contact says that the text was taken straight out of an updated draft of a Soviet Army field manual that never got printed due to the end of the Cold War. It contains a better understanding of Soviet tactics over the
old manual which some people are still using as a valid resource!