These "dynamic balancer" things are becoming the new fad among motorcycles. It's a flawed idea, and they base it off the idea that "light" spots in the tire are always accompanied by a "dip" in the internal wall proportional to the amount of imbalance. Does that sound very likely?
Once the wheel starts spinning, all the little beads/fibers/whatever are blasted against the inner tread, and held there quite firmly. If there is a "low" spot inside the tread, more "stuff" will collect there to create a uniform layer of "stuff" inside the tire. However, say there's a big flat spot on the outer tread from say locking up the back wheel for a ways, that threw the balance out. The inner wall of the tire is unchanged, therefore the distribution of "stuff" isn't going to change either. Any vibration or unbalance isn't going to overcome the natural centrifugal force.
Just get a plugger kit. There's MC tire specific mushroom plugs, but I've had good luck with standard radial car tire plugs. Get the $8.99 kit with a bunch of the tar-soaked strings, the reamer tool, the big needle, and the tube of cement. I plugged my Metzeler when it picked up a screw and now over 4k miles and many jaunts to 130+ later, it's fine.
