He would certainly not advise you to move outside of Germany, in view of the tremendous needs in that country. However, he approves, if you find it financially possible, of your moving to Dortmund where as you say there are no Bahá'ís, and which is one of Germany's major cities. This would indeed be rendering the Faith a valuable service at this time in setting an example to others. Either Dortmund or Berlin would be highly acceptable, whichever would be easiest for you.