Well, after using the Colossus grinder a bit, I noticed that the lower funnel felt slightly warm compared to my home grinder with the same burr. Since I dose 20 grams at work and only 16.5 at home there's more opportunity for the burrs to warm up. Additionally, there's more static, even with RDT.
I had glued the variable speed switch to full speed to keep the momentum high when I was having all of the drive belt issues. The speed is definitely faster than my setting at home, which helps explain both the warmth and more static, due to the friction and perhaps evaporation of the RDT misting. The static is a little less with beans right out of the freezer, which seems to support the heat causing evaporation notion.
Although I realized fixing the speed issue would require a new switch, taking a lot of things apart and rewiring, the more I thought about it, the more I was resigned to address the issues. Unfortunately, an exact replacement switch was not available without getting the full drill, so now in addition to a new switch, I have a backup motor.
Here's the new switch, and instead of cutting the entire trigger face off, I just trimmed it and melted the coupling nut into it, gluing it into place.
Fortunately everything went really well. The speed control works, even at fairly low rpm with beans. I'll have to test it a bit more, but it was working at a lower speed setting than I intend to use. Also, the static seems much better. I'll give an update and another sound reading once I get it back in the office.