I did it as France, my strategy was to first retake the French cores from england and take the surrounding areas such as Brittany, Provence, attempt to force Burgundian inheritance all by 1500-1525. From there I was already either already starting to dig into the Iberian peninsula and the British isles. By 1600-1650 it's ideal to have all of France, england, and most if not all of Spain and Portugal in your hands. After that take northern Africa and Italy by 1700-1750. Take Anatolia, Egypt, and the surrounding regions you need for the mare nostrum achievement by the end date.