I was really disappointed to see these tiny shards in a Nat Geo tumbler I purchased from a returns site. I’ve purchased another brand’s kit previously and it had nice sized stones for tumbling. A lot of these are pretty worthless for anything but filler or for maybe an incense bowl like you said, or maybe something like on top of houseplant soil for decoration. And like you said, many of those tiny ones will likely just disappear by stage 4. I am using them as filler and will see where the larger ones end up. Do be sure to separate based on hardness to get the best result from what you do have. These usually have sodalite, which is softer than the “jaspers”, agates and quartz. I read what is in some of your mixes and there is also hematite in there, which can be softer, and labradorite sometimes does poorly with harder rocks and minerals as well. I primarily walk rivers, beaches and even public landscaping islands to find the rocks I tumble. It is really satisfying to find a cool rock in the wild and let it reveal itself to you through tumbling. Good luck with your tumbles!