Good morning, Matthew, I feel your pain. I’m American and have been struggling to find some 18th century ancestors, too. This website does not have the historic holdings indexed. You need to plow through every name in the appropriate church books to find info on Rudolf. You are far ahead of many of us whose family members emigrated, and no one now knows what towns they came from. Do you think Rudolf was Protestant? Then you have a good chance of locating him once you study the Danzig documents for 1864. If he was Catholic or Jewish, his record will not be on Archion. Hope this helps and good luck.