Note: If you’re interested in having a bearingized counterweight made for you, shoot me a pm.
V 3.0 EDIT- THIS DESIGN IS CURRENTLY RETIRED. SIMPLY PUT, THE OTHER DESIGN WORKS MUCH BETTER.
The best working counterweight I’ve made yet. The new set up is inspired by Fjh123.
The rubber o-ring in the delrin ball holds the bead inside of the ball. the bead can be removed with a slight flick, but won’t come out in normal counterweight play.
Even the smallest amount of string tension is now dealt with VERY QUICKLY. Seriously. It’s almost scary.
Delrin 
finally got a drill press so all of these are precision made! no more hand drills.
the delrin balls are 1" in diameter. A little smaller than spintop buttons, but plays better IMO.
UPDATE! bearingized yoyofactory spintop button. First off, I would like to say that the spinstop plastic is a major pain in the *** to work with. Other than that, it plays just like a regular spintop button, but without tension issues.
Note that the spintop button was beat up before I started the mod. the mod did nothing to damage it
The hole is a little off center, but I’m using a hand drill and it was my first one.
Duncan dice
Plays amazing.
Instead of the bead idea that yoyojam had, I used a string bud from astrojax aquas. This makes it viable for both regular 5a tricks and astro type tricks.
The bearing helps tons with string tension. You can hear it adjusting when you’re doing fast paced tricks such as electric fan. The string bud sits on the bearing and can spin very freely
The bearing and string bud also significantly increased the weight of the counterweight. It now weighs about as much as a yellow bouncy ball.
Also, would it be a good idea to use a dice that doesn’t weigh as much so it will weight closer to Duncan Dice? By the way, I’m not putting on the end thing that does the double dice.