I just happened upon your post and wondered if your Gustave Petzsch could be my Gustav Pietch. Although mine is supposed to be married to a Johanna, the same as my grandmother Johanna Pietch. This is, I know, a shot in the dark....but maybe?
I really don't have much information about him and am just starting to delve into my family, now that I've done as much as I can on my husband's family.
Let me know what you think.