Any views on what time period(s) this "Prussia to US migration" project would cover? Prussian territory was changing over time, and my main interest (or ability to contribute) would be around emigrants from the Kingdom of Hanover to the US during 1830-1870.
If you look at US immigration from the perspective of the emigrants, they were emigrating from countries that would later become the Deutsches Reich. Hence, a one place study-based view of emigration would identify emigrants from a single village or parish. Since this can be attributed to one location, it might still be allocated to different countries, e.g. one village could have been a part of Prussia in 1806, but then only later from 1871 onwards. So this causes some issues.
In addition, the ships that took passengers from Bremen or Hamburg to the immigration points in the US (New York, Baltimore, New Orleans etc) would collate passenger from many countries (Prussia, Hannover, Oldenburg,...). Would you want to look at only a few passengers on a ship, or would you not want to look at a full voyage? See
https://www.wikitree.com/wiki/Space:Tuisko for an example that is leaning to what the Prussian/ Australian team have done, but lacks in "completeness".
Ultimately, my question is - would it make more sense to do a Germany-to-US migration project. But I might be opening Pandora's box here...
Sven