Well Friends, just a silly thing, but I´ve find it very useful.
Omit R12 (22k) and Replace R11 (33k) for 10k. (or something close).
Put a 25k Lineal Potentiometer and connect Lug 2 to that resistance and Lug 3 to C8 (47n) and Lug 3 of the Volume pot.
Now, you´ve got the switch values around the extremes of the Pot annd all the Intermediate Values Between.
That made my Ego Driver Even More Juicy and Tasteful.
Hope you like it.