I wired the switch as below:
The black wire is normally wired to the sleeve and the white to the tip. Flipping the switch reverses the leads. I marked the "reverse side" of the switch "R" so I can quickly tell which wire is quieter. I plugged the jack into an amp input, attached a capacitor and turned up the volume. Touching the capacitor outer cover ONLY, you get a notable increase in hum. I turned the master off, flipped the switch and turned it back up to the same level and retouched the cap cover. It's quite noticeable that one end is much louder/noisier than the other. The only exception was with a ceramic disk cap I tested. I've seen people also plug this kind of test into a DAW to visually see the differences in signal gain depending on orientation. I marked the caps with a black Sharpie on the foil side. You can see they are not all oriented to the label, necessarily.
We'll see if this makes a difference in my build, but if you like this design, it couldn't be easier to build and the difference in direction is truly noticeable. Cheers.
