I can usually get the required provinces before 1500 as Friesland. Initially the Hansa is likely to accept and alliance, so take advantage of that. Gelre and East Frisia often ally, again something you can exploit. Once you've expanded a bit, the Hansa will probably break their alliance but you'll be ready to ally France. Then simply beat up on Burgundy/Austria until satisfied. Remain allied to France for as long as possible; you'll often be able to opportunistically seize Spanish or Portuguese colonies when nobody is looking.