ISSA - International Slalom Skateboarding Association

So what are the various theories behind the number of balls per bearing?

A conventional bearing has 7 balls, but I've seen:

Reflex 9 balls
Reflex 8 ball
Bones Super Swiss 6 ball

The Super Swiss 6 ball theory is that larger balls in the bearing are like larger wheels. They have a higher max speed. I guess the 8 and 9 ball bearings would be slower but accelerate faster.