Hello John,
I think you should also try posting to the Oldenburg list. I have seen the Gieske name in the parish of Neuenkirchen-Voerden. It is right on the border between Oldenburg and Hannover, and your information says your great-grandfather was born in Vorden.
I believe a person from Paducah, KY posted a question about that Gieske family six to nine months ago on the Oldenburg list.
If you are in Ripley county, I believe that is by Oldenburg, IN, and a lot of people from Oldenburg and the surrounding Hanover area settled there.
If you find your family was in Hannover, you will want to do research at the Diocese in Osnabruck. I think that you have to make an appointment in advance to do research, and that there is a waiting list.
If they were from Oldenburg parishes, you may want to wait until you get home to do research. The Oldenburg parish films were filmed by the LDS and are available all over the US. The films are restricted in Europe, and you would have to travel to the archive in Vechta to do research. I think the archive has relatively limited hours which it is open, and I assume if you're coming from Dresden, the travel time would be substantial.
Good luck,
Don Meyer