Just did a bit of minor surgery to this pedal. The tagboard layout called for a 470r current limiting resistor for the LED. I thought that was a bit low so used a 680r. But the LED was still far too bright. Desoldered and replaced with 2k2. Now it's just right.

Also found this video from That Pedal Show. It's pretty much the same as the Pete Thorn one, but longer, slower, and with more detail. I like how they start with a description of a guitar tone control and then use that to explain the effect of signal chain capacitance.