Hey Andre. And, yes, even this morning I came across a few van Amstels in New York. Have you been able to connect your tree to the emigrant van Amstels? If so, I think the best thing for the moment is to search for the American van Amstels, find the living descendants, and then add them to your family tree'. They will get instant notification.
On the other hand, what's the name of your project? When I see an American van Amstel, I could add them to your project.
We are with a few people right now who are matching and merging TONS of duplicate descendants from New Amsterdam - so I'm coming across familiar names all the time now :-)