I used to know people who were very into historical (and detailed) board games.
Having said that, the only thing I can say about this is "HOLY MOTHER OF CATS!"
Playing time with 10 players is listed at 1200 hours.
That's for 2 teams, 5 people per team. I understand that, in terms of the game, Italian troops require an extra unit of water per turn, because they subsisted largely on pasta. Even I am not this nerdy.