10-cent schematic?

Hello,

I have used the search function and over the past few weeks I have read everything I could find about the '10 cent tuning' .
Of course, I also looked at Andreas' '10-cent tuning' solution (pictures).
I would be interested to know how you implemented that .
Where, for example, did you install your potentiometers and on/off switches? (e.g., inside the interior, where exactly)?
or perhaps leave everything in the engine compartment after determining the resistance value?
I would also appreciate a circuit diagram with a potentiometer and 2 x 4148 transistors .
Pictures are always nice to look at, so please post some .
This is probably of interest to other users as well .

Have a good evening.
Best regards,
Andy