RTFM. There is a diagram in the Build Doc that shows how to wire the TONMANN tone bypass. There is also an instruction for wiring a Tone TwEQ in place of the stock tone stack.
If you want to string 6 diodes onto one side of a DPDT, you will need to solder three together facing one direction and stack the 2 ends onto the DPDT next to another three facing the other direction. Obviously, the middle diode in each string is not touching the board.
When adding diodes in a string, you will increase the Forward Voltage, Fv, which will increase the signal level that the string passes. Since 1N34A are germanium that pass a lower Fv than the 1N914, you may wish to use 6 on the 1N34A side and only 4 on the 1N914 side of the DPDT. This will result in a closer signal level between the 2 positions of the switch.