Well there is just only one boat left to charter. All others are already gone. I'd need to be decided by tomorrow afternoon -German time that is. (I'm somehow "disappointed" that even some of those being confirmed didn't reply to this thread or my email since three mo's ago. Makes planning kind of hard)
The radio tower has still space available. A six course dinner would be served in the revolving restaurant atop the tower.
Costs in either case would be quite the same.