everything about his p[osts was "do everything the most efficient possible way!" which is power gaming bullshit
There's no need to go running around being a jerk. If you want to discuss/debate his advice then you can do so politely. Just because he is offering advice
you wouldn't want to take doesn't mean OP doesn't want it.
To answer the OP, I think the basic strategy is to give up all continental provinces in the HYW except Calais. This should give you an event that will let you also give France Calais in exchange for stability and some other bonuses. As much as I love fighting to keep Calais until the Staple Port decision, I ultimately think it isn't worth it. Mercantilism is not that important when you're England, as you'll have light ships everywhere to bring in New World trade, and you can conquer plenty of land for your trading companies because you don't have to fight any wars on the continent.
Since you want to take Scotland at some point anyway, and France might never stop guaranteeing them, using a diplomat to generate a claim immediately is a good idea. If you can declare war on Scotland before peacing out with France, they won't be called in. Even though France would do nothing in such a war militarily, they do cause warscore to be calculated differently and they will cause Scotland to refuse peace for a much longer time, which you don't need.
I don't think you can sell Calais to Burgundy (probably rivals), and Austria can't core it so they won't take it. I also don't think selling Labourd to Navarra is worth it, since France and Spain will fight anyways and I think you don't get the event to abandon the continent if you keep it.
I am personally uninterested in fully optimizing my gameplay since it is easy to become too big to fail, so you may not want to take my advice. Just do whatever you want to do, and as long as you don't get eliminated from the game, I think it'll be fun.