I got much of my info from books of old documents etc. and old books, from personally visiting the Schenectady Historical Society Library, the New York Historical Society Library on 77th Street NYC, the New York State Library in Albany, NY and the New York Public Library in New York City.
Also I'm nice when I go to these places and I let them tell me. That I might know more than them doesnt matter if I want more info. Genealogists are proud of their craft and hate know-it-alls. I just go in, introduce myself, act nice and ask for a certain family, and shut up and listen. Well known names in a certain area are usually at the finger tips of the genealogists. They know just where to go to get certain books to zero in on the exact info from the umpteen hundreds of shelves that would take you and I days to find. And they are usually very helpful and glad to be of service. And you can usually glean something new from just listening to them.
Some of the info comes from old Holland Society books or the New York Genealogical and Biographical Record, or books with old baptism or marriage records.
Besides Symon Symonszen Groot (1620-1690) I have several other allied families. As I know the names I want to find, i8 can skim a lot of material in a hurry...
I also learn who the siblings are and who they married too, though, because often the ones you want were "witnesses" to baptisms, weddings, etc, and that puts them in a certain place on a certain date. Often when they became ancient grandparents they were "witnesses" also. Was that 80+ year old the one you were looking for? Yes, ofen due to reverence for the position in the family more than the confidence that the ancient could raise the child in case of the death of the parents. So dont rule out baptisms for other family members just because Grandpa has one foot in the grave..
About Symon Symonszen Groot, I dont know what was new to you. The info has been in several books etc, and in the Internet. However, I'm collecting paper proofs in order to join the Dutch Settlers of Albany, probably using the Groots.
Looking at the photo copies in my files quickly I find this about Symons job on the Prince Maurice in a story about his inlaws: The New York G&B Record Vol LXXII, 1941 P20, in the article, The Family Van Antwerpen in America, by Lee Douglas Van Antwerp. "Daniel Janse married Maria Groot, the daughter of Symon Symonse Groot, who came to the colony as a boatswain of the ship Prince Maurice in the service of the West India Company (PS). He is the common ancestor of all the Groots who came to America and settled at Schenectady in 1663 (EHS)"
From Contributions of the Genealogies of the First Settlers of the Ancient County of Albany, from 1630 to 1800 by Professor Jonathon Pearson 1976, P57 "Groot, Symon Symonse Senior, a servant of the Dutch West India company, was at Bevcerwyck in 1654. He was one of the first settlers of Schenectady." And then his sons, Symon Symonse Junior, Abraham, Dirk are listed, but not the dau, Maria. Her I find under the her husband's name. "Van Antwerpen, Daniel Janse and Maritje Groot." (I know that Maritje is a Dutch nickname for (Little) Mary, Marie, Maria) and I know that that is her) then it gives their children.
and so on. I dont know what was that I gave you, but I hope it helped.
I'm making files for my different family lines and I have the Groots under DUTCH (meaning Dutch to the US), as there is not much there. Some families, like the De Forests, have their own file.
I hope this has helped.