Easy Listening on bottle cap with recessed tip.
https://www.youtu.be/8BmOLwAvf3cWith this I got a spin time of 15:08
"Edit: Update, 04.04.2021 - Spin time 19:05 - some basic centering and balancing did much. This is my best time I reached with any top so far."
The tip is not perfectly centered yet, I did not find a good way how to do it. So I didn't even bather to balance it, because the reflecting surface for the laser method is also a bit poor.
On a large concave mirror (tip not recessed in that case) I had it spinning for 8:51, but then I tried to make improvements centering the tip and tensioning the spokes - the a nylon spoke broke, I could not get it back to that time with protruding tip. So I moved to this recessed tip for now.
Still want to find a better rigging method and a material suited better for spokes. Might take a trip to the fishing supply store next week - if it is not closed to to a Corona lock down.
Looked at that video again: almost by chance, it resembles the von Braun space station parking close to the orbit of Saturn ..........