Hi!
Thinking a bit more about timing, it seems that the second half of March is a good idea.
April is a bad idea, at least for the first two weeks, as this is easter holiday time in a lot of German states. This will cause lots of tourists, as well as full hotels, trains, flights, etc.
So I'd propose something like four days in the second half of march. Should we try to overlap/extend a weekend? I guess this would help people with e regular dayjob, as not as many holidays would be required.
If there are no objections in the next 48 hours, I will talk to C-Base about availability during that timeframe.
Regards, Harald