More info of the parents of Jan Pieter I don't have. Only that they had 6 children, of which Jan Pieter was the eldest. I have been searching for that for a long time. That info must be in Leer, Ostfriesland, Germany.
There is a branch of Sprock in California that also comes from Ostfriesland. And then there is another branch in Friesland, The Netherlands which also comes from that area.
As you can see I am just one brother/cousin away from connecting these branches. But since I am not very often in Europe it becomes difficult.