Well, with Liberty desire, PUs for big countries is pretty well out, I'll share this now.
So, a strategy I've used that seems to have never been mentioned (and looks mostly useless with 1.10 for catching big fish) follows:
Rather than sitting around waiting for a country to have your dynasty on their throne, put theirs on yours. Simple and direct.
To do this, marry the target country, ally them, marry another large country, a typical example would be both France and Austria.
Kill off your heir when your monarch is hopefully pretty old. The PU warning should show. Take your French ally into war with Austria after putting your monarch on a horse.
Fight the war, draw it out until such time as your monarch dies. France will give you a noble from their dynasty, albeit with a weak claim starting out. The next heir, in my experience has an average claim followed by an heir with a strong claim - just a note that might matter if legitimacy is important for things like unrest, etc.
Done, your dynasty is now on the throne of France (vice-versa, but the same effect).
Likewise, every throne with France's dynasty is now shared by you throughout Europe.
From there, getting PUs all over Europe is a matter of timing and choice. The lucky part of getting your dynasty on target thrones is over.