The video gives a good concept insofar as a measuring ratio and how to use it. However, there is one important point left out of the narrative and instructions. The directions say to run the grinder for 20 seconds. Well, depending on the material that might just melt the dubbing and ruin the grinder. Example would be if you used a yarn made with a high percentage of any of the plastics. Aunt Lydia's Sparkle Yarn comes to mind. The heat generated by the grinder will melt and fuse the material fibers. I mix this stuff all the time and learned my lesson immediately after my first attempt years ago. When using the synthetics, just use short bursts of say 2 to 4 seconds. It may take a few bursts but I think you'll find the results will be better then one blast lasting 20 seconds.

Allan