The 6-Way rotary switch is the last part of the Varitone circuit, and its function is detailed in the Varitone article I linked to in the first post of this series.
The earliest switches consisted of individual ceramic disc capacitors soldered to the switch poles.
Then in the '60s, Gibson changed to the Sprague PEC-1007, which was a multi-value capacitor chip (and presumably easier to assemble).
Wanting to completely geek out, I sat down one day and measured the capacitance values for the '50s, '60s, and current Gibson Custom Shop switches.
As you can see, even in the bypass position, some capacitance is present. There is a schematic and mod out there that shows you how to rewire a stock Varitone to be truly bypassed in the first position, but I have not tried it.
Part four will wrap up my thoughts and introduce you to the BMF Effects ES-Box.
Illegitimi non Carborundum
Scott @ BMF Effects