Have you floated this idea with anyone else you know in Germany? I'm not asking if you're ready and willing to get to the threshold of 0.1% of German voters (~7000 people). I'm just thinking more feedback, and others involved, whether one or two, might help. Also, you could just talk to lots of people in your local network about it. As far as I can tell, people might be loathe to make big commitment like helping you launch a party, but are willing to do trivial favors like putting you in touch with a contact who could give you advice on law, activism, politics, dealing with bureaucracy, finding volunteers, etc.

Do you attend a LessWrong meetup in Germany? If so, float this idea there. At the meetup I attend, it's much easier to get quick feedback from (relatively) smart people in person, because communication errors are reduced, and it takes less time to relay and reply to ideas than over the Internet. Also, in-person is more difficult for us to skip over ideas or ignore them than on an Internet thread.