Hi bluestraveler,
Like Larajean_p said, I also believe this preference section was optional. I am not sure if there will be another opportunity for one to state preference, but if you do have a strong preference and find out you have been accepted on the Germany side, you could probably get in contact with someone there to figure it out. I commend your lurking and will most likely be doing so on a weekly basis myself! It is all very exciting, and it is nice to share in the entire spectrum of emotions we all will/might feel during this second waiting process.
At any rate, if you aren't sure you entered anything for that section, you can always peak back at your Embark application, as they are still viewable.