Rather than holding this fidget with thumb and forefinger, this fidget is held on just the forefinger.  The design is based on adding three poles to a bearing.

The three weights are 3/8 nuts. 

It took a few minutes of turning the outer ring on the inner ring to get rid of the small stick slips. 

Rather than fabricating a Separator to keep the rollers from hitting each other, the inner race does that with cylindrical holes for the rollers' axles. 

I used super glue to ensure the nuts stayed in place.  The clearance was loose.