Hi, thank you for doing this scenario. I have long dreamed of playing it. There are a couple of historical inaccuracies in the first place in1920 There was no Soviet Union. There was a Civil War in Russia between the Russian Empire and Soviet Union.Also on the territory of the Russian Empire there were other states such as Ukraine and Belarus who also fought the RSFSR (the communist state in the territory of modern Russia) and the borders of Poland were not like they were before World War II . Also the Soviet Union fought with Poland in 1920 1921.
There is a map of Civil War in Russia.