yeah , that is a good idea.
I’ll make a jumper for it, so that if you do not use this option, the stage is grounded.
(like in the schematic above )
Maybe I’ll add a “experimentation area”.
Question: Shall I leave out the resistors + capacitor, like in stage 1?
Maybe I can fit them, but if it is an experimental area, It might be useful not to have a predetermined use.