Very nice circuit and extended version of the SHO.
Here's the schematic with an alternative tone style:
I didn't try it, just simulated.
The orgiinal one appear more treble cut. I changed the tone wiring that leaves more treble/presence. In the new Tone we could use even a 22nF cap, and I think it's better a Log pot instead a linear. The new Tone cuts the treble at the same way at minimum, but "boost" more treble.
Maybe it's possibile to add before the Volume pot a RC low pass filter (1k+3,3nF?), if it's too much harsh at higher setting.
The R6 resistor could be a 5k Rev Log Gain pot (Crackle OK) like the original SHO, or we can use a Pre-Gain pot (Crakle it's NOT OK). I'm not sure about the position. I see some SHO version with a 1M Log or Rev Log after the input cap C1.
About C1, 1nF seems a very small input cap, but my emulation software tell me that even a 2.2nF cap produces a certain increase of gain/low end.
I build pedals