Kelvin said:
If you make it a vassal, the events are geared for the conflict, and if you take provinces they will a) have a 30% income penalty because of the wrong culture and b) present France with a permanent Cassus Belli against you (until you annihilate France, that is
).
So it's up to you to decide on the course you want to take.
In the GC, you start with french culture, so you won't have the wrong-culture penalty. Also, with the GC, the goal is either to completely get rid of french provinces and play an insular (
historical) England, or to win the Hundred Years War. So, go for the win, keep the french culture, ultimately annex France, and go on as the number first country.
To keep french culture, you have to make sure you keep the provinces you start with & conquer Picardy.
You start in a defensive war, so every province you take is 1 BB apiece, so use that. Make separate wars with each vassal of France, taking their spare province (
don't annex Orleans, and keep it an alliance-wide peace on your side, you want to keep the war defensive). Then, take all remaining french provinces (
easy to do, mostly plains, and you have enough leaders to be sure to steal the sieges of your allies). France will offer you a generous peace (
be patient enough to get a good offer). Usually, you end up gaining three provinces from french vassals and at least 5-6 from France. This leaves France with only a couple of provinces. In the next war, either take the remaining provinces if it's a defensive war, or (
preferably in defensive war, or obligatory in offensive wars) force-vassalize France. Build up relations, let France force-annex its vassals (
DoW them if need be), and ultimately diplo-annex France. For less than 20 BB total you'll be the rightfully King of France & England. It's up to you to take other provinces from then on.
