[Ger-Poland-Volhynia] Baptist pastor Kelletat

[Beatrix Hughes]

When I was going through some of my grandmother's papers I found a note in her handwriting that said she was baptized by a Pastor Kelletat in 1910 in Graudenz. I wasn't aware that she was living in Graudenz in that year. I have some missing years to fill in between 1900 and 1921. I thought if I could get info about this pastor it could give me some clues. I found out through the internet that there was a Pastor Hugo Kelletat in Graudenz who had a son who became a famous musician. Everytime I search for info about Kelletat I end up getting sites referring to his son. What I'd like to know is:
What was the name of the Baptist church in Graudenz?
Was it a large church or a small one?
Was Pastor Kelletat a popular speaker who could attract audiences from other parts of Prussia? (I'm wondering if my grandmother made a special trip to that church or if she went there regularly)