Hi there!
First, I want to praise you for starting this never-ending marvelous challenge. WW2 is not and easy subject to make a scenario, even only in Europe.
Second, I want to give my own knownledge to your availability, here are some corrections and proposals considering Finn-Russo war (aka Winterwar):
1. Several cities are mislocated:
1.1 Tallinn should be at south of Helsinki, replacing your Tula
1.2 Leningrad should replace your Tallin at the extreme east bottom of Gulf of Finland
1.3 You can replace your Leningrad with city of Petroskoi, which was captured by Finnish forces in 1942.
1.4 the city between Tallinn and Leningrad should be renamed to Narva.
2. Proposed cities:
2.1 Vyborg (Viipuri in Finnish) was more important city for Finland than Tampere, it is located about 100 km from Leningrad northwest.
2.2 Petsamo was the only Finnish city (or town) at Barents Sea, and it was given away in peace treaty 1940. It is about 50 km northwest from Murmansk. There are several important mines that Sovien Union wanted from Finland.
2.3 Sortavala, a little town at the northern shore of Lake Ladoga (first lake to east from the Gulf of Finland, the second is named Lake Onega). This town makes Finnish border look a little more like it was at 1939.
2.4 Petroskoi (beloning to Soviet Union), a little town at the western shore of lake Odega.
3. Overlay
3.1 There should be railroad from Leningrad to Murmansk. The railroad goes along White Seas coast.
(Soviets carried several divisions from southern parts of Soviet Union with summer clothes to occupy Finland at -40 degrees in Celsius, their first task was to build 300 km road between railroad and Finland's border as north as Oulu.. 30% died before border.. )
3.2 Iron/Aluminium mines next to proposed city Petsamo.
4. City properties (I already corrected into my copy, so I don't remember if some these exist in the original)
4.1 Helsinki, add at least hospital, university
4.2 Turku, add at least university, cathedral, hospital, coastal fortress
Those were the straters, I will continue when I get into the game, these notes were made from the editor.
Carry on, I give my support if needed.