My tactic was a bit different, I formed the Netherlands from Gelre with all the entire low countries under my banner before 1500, this was the second time and even more succesfull then the last time... My experience is that containing France is much easier when you ally them, they are queit faithfull and will follow you in almost every war against HRE, Burgundy and England. And as long as you are pulling them into wars, they don't declare their own wars. So I used them for 40 / 50 years. Kept them busy with my wars in which they didn't gain anything. This way I had France 40 years into the game without gaining a single province. While I had Burgundy release low country states in every war and vassalized them afterwards to keep AE relatively low. Because Castille and Austria got their time of peace they have become stronger. After having a solid southern border with France the alliance will break eventually because off borderfriction. But France now has neighbours that are up for the fight. I had allready allied Denmark and when my vassals got annexed one by one I also allied Aragon, Ireland and Britanny. To keep England, France and Castille from expanding there actually. I now have France contained, Austria grew strong because I kept France in other wars in the first decades. Castille is allied with Austria and France can't beat them both. Britanny is my ally and will make me leader if France declares war with them, pulling in Denmark and Aragon. Declaring war on Aragon pulls in me, Savoy and Austria which is again to much. It isn't that they haven't tried to break out, but I've got them locked since their only allies are England and Hungary. I don't feel like taking out France either, since I'm having problems with the OP Castille, Austria and Portugal alliance. I really need a relative strong France there because I can't effort that Castille or Austria fil in that gab.
So I'm pretty much balancing the game now. I haven't expanded anything in europe for over hundred years now, France / England and Austria / Portugal / Castille seem to be perfectly balanced as neither side declares war on the other. Which is perfect for me, tipping this balance in favour of either one of the alliances would be a real problem for me. It seems though that France / England are relatively contained, while Castiles and Portuals colonial possesions keep growing and Austria steadily expands inside the HRE and east. I'm foreseeing troubles now that my colonial possesions are growing towards those from Castille. But I'm really scared of declaring war at this point since there is really no saying what will happen then. I hope France / Engeland gets into a war with them soon and take adventage of that... Otherwise it's a real problem, since every year I wait Austria and Castille grow stronger.
Anyway I think that since as the Netherlands you'll be going colonial you can't really afford it to destroy England / France, it really gives Castille / Portugal to much free play in the Americas. In the late game you'll regret it that you don't have something to counterbalance them. At least in my case I'm glad that France and England still are arround and are colonizing. They aren't a thread to me, but strong enough to be usefull when they get into a war with Castille / Portugal so that I can join in to give the finishing blow.
With allying them you should be able to controle France and their wars the first decades, give Austria a head start and they'll do perfectly fine containing France later in the game and otherwise you can always step in with you allies if Austria is losing their war.
So I'm pretty much balancing the game now. I haven't expanded anything in europe for over hundred years now, France / England and Austria / Portugal / Castille seem to be perfectly balanced as neither side declares war on the other. Which is perfect for me, tipping this balance in favour of either one of the alliances would be a real problem for me. It seems though that France / England are relatively contained, while Castiles and Portuals colonial possesions keep growing and Austria steadily expands inside the HRE and east. I'm foreseeing troubles now that my colonial possesions are growing towards those from Castille. But I'm really scared of declaring war at this point since there is really no saying what will happen then. I hope France / Engeland gets into a war with them soon and take adventage of that... Otherwise it's a real problem, since every year I wait Austria and Castille grow stronger.
Anyway I think that since as the Netherlands you'll be going colonial you can't really afford it to destroy England / France, it really gives Castille / Portugal to much free play in the Americas. In the late game you'll regret it that you don't have something to counterbalance them. At least in my case I'm glad that France and England still are arround and are colonizing. They aren't a thread to me, but strong enough to be usefull when they get into a war with Castille / Portugal so that I can join in to give the finishing blow.
With allying them you should be able to controle France and their wars the first decades, give Austria a head start and they'll do perfectly fine containing France later in the game and otherwise you can always step in with you allies if Austria is losing their war.
Gotta leave Austria big enough so that it'll have rival status to my allies.
