Do you have link to the West Prussia census documents
The census of 1905 is available at one of the online databases of the Polish state archives, if I recall correctly. Can't remember which one, but I'll try to find out. Equally valuable is the "Gemeindelexikon für das Königreich Preußen", provinces Posen and Westpreussen, which is based on the census. Also available online at one of the Polish state archives.
The census that is interesting for you is the one of 1809, though. I have only seen parts of it floating around the web, never the complete one.
Here's the link for the Gemeindelexikon, Provinz Westpreussen: kpbc.umk.pl/dlibra/doczip?id=31688
and the main site of the state archives: archiwa.gov.pl/?CIDA=43
I stand corrected: the 1905 census is not available. Think I mixed it up with the Gemeindelexikon. Sorry for that.