Hey Marcus. I haven’t tried this but from I can see, following the guide above and the V5 schematic, you could insert the pot between C8 and the junction of R2/R3. I see only 2 ways of performing it. You could have a sister board attached in place of C8 as the cleanest way (my favorite) or cut the trace between C8 and R2 and solder wires to C8 leg and R2 leg (still effective). That is the only possibility that I see for insertion. Perhaps a keener eye or someone who has tried this can chime in. Cheers