I play bass - I got no business up around 8 kHz
FWIW, my accompanying spiel on youtube clearly explains why I used the caps I did. I needed to get my ears around what the different values actually sounded like through my rig & recorded, particularly down the lower end.
Now, with the 6-way I installed on my P bass with flats, there is little or no difference between the 2.5k cutoff cap and the bypass position (other than a slight volume increase in bypass). I've done 5 gigs with that now, and I find it to be quite USEFUL.
Capacitor values aside, the important point here is that if you have the competence to install a Stellartone, then you can make one yourself that works just about as well for a fraction of the price.
c-