The Chinese did not want the low grade Dutch silver coins . Instead they wanted gold coins from the Dutch traders . You are correct as far as the riders go . Cornelius
The coins in circulation were : Albert & Isabella 1598- 1621 Philips IV 1621-1665 Karel II 1665-1700 Luik, Maximilian Hendrik 1650-1688 . So the coins to be found on the Schoonhoven could be by Albert & Isabella ( as posted by you ) or Philips IV ........ Cornelius