How did I chose the bearings I would use for TX wing cuts?

I made a YoYo Dynamometer …

Tried 7, 8 ,10 and 11 ball ceramic hybrid bearings.
Looking for spin time between 8000 and 2000 RPM’s’ where it all happens.
I was betting on the 7 ball but the best was the 8, same diameter ball as the 7.
Far less revolutions to travel around the inner race then the smaller 10 and 11 balls.

It’s hard to see but it’s a YYJ AXIOM spinning at over 5000rpm’s after 1min 16 sec.
I test with undersized throws.