Thank you for the very interesting post. Patzer family migrated: West Prussia, Poznan region, Kujawy region, Central Poland, Lublin region, Volynien. It was after dividing of Polish State since about 1790. We in Poland are now reseraching in Central Poland and Kujawy region. We are planning to research other regions too. You know the route of migration. So we will look for Patzers in West Prussia at the end. Your hint about East Prussia have a great value for us. We will trace back from East to West Prussia or in opposite direction.
There is a lot of archival materials in Regensburg in Bayern, Germany.