The boost switch does not have any effect on the noise. I grounded the volume pot to itself (back of the pot can), and the ground tab on the tone pot is connected to the back of the can by way of the .0047 uF capacitor as shown in the chassis layout diagram. The nuts holding the pots on are screwed down pretty tight, so I think the pots are grounded well. The next time I get a chance to troubleshoot some more, I’ll try to jumper a different ground to the pots, to see if that has any effect.
I uploaded a few photos of the chassis to my profile page under the photo album “TAN 2 Stroke.” At the moment this seems to be the only way I can get pictures online. If there are other photos that would be useful to see, I would be happy to take more pictures and post them to that album.