I have corresponded with scores of Gehlings unrelated to my line. Some of them are in Germany. Some of them have Prussian origins. I would be happy to forward any of your inquiries to them and I am sure they would respond to you.
I paid a researcher in Germany to provide me with information. It seemed like a lot of money, over the course of a year, about $400. But it was a fun adventure.
The big pay off was finding a cousin, however related through a common ancestor who was born in 1801-so not a close cousin, who is a computer programmming whiz. He designed the beautiful site I mentioned in the beginning.
We collaborated on the family tree. With my research and his family input for corrections and additional information, and his artistic editing, we have 2 viewable family tree versions at the site. It is truly a work of "art".
If you go to the site, there is a "slide show" with a wonderful selection of vintage photos of our family line. In addition, there are wonderful pictures of historic Bavaria there. Many links are embedded into the side bars for additional information and even just for "fun".
Please feel free to visit the site and to send me an inquiry that I can forward to correspondents who are probably related to you.
Sincerely, Kate McIntosh at firstname.lastname@example.org