It would be very nice to receive that Slingerland tree when you have time again!
By the way, you know that Jan (John) Slingerland, married to AMP Ziegler first was married to M. C Hilker?
I don't know how far your interest goes, but if you want, I can also give you names and dates of the parents of Aaldert van Ingen.
A small correction: Pieter Slingerland and Guurtje van Ingen lived in Haarlem after the marriage, not in Amsterdam as I wrote earlier.
For now, have a very nice Thanksgiving holiday!