How long is a Conquest supposed to last?

I just started the game and I'm loving it. After the tutorials I played a game of skirmish with Atreides and won (on easy of course). Took me about 4 hours and I really enjoyed it. Decided to start a Conquest with Harkonnens. Won the first region in about 3 hours. So now I have to do this 8 more times plus destroy another faction or befriend the Fremen? How long is a game of Conquest supposed to be? What's the quickest way to win it? I'm not rushing it, really enjoying the game, just want to know if I'm doing something wrong.

Ps: both times I won the game with about 22k hegemony and controlling 4/5 Council seats.