For anyone interested, I did this in the end on 4 kits/2 two-in-one pedals.
As discussed, I used a center off switch on every board to have two diode clipping options plus a diode lift option. I also used a 500k gain pot in the first circuit of each pedal (as in the high gain KoT mod).
Really happy with the dynamic and gain option this gives.
Compared really well to a friends Analogman KoT and my vero KoT clone. Only major audible difference when build as per the PCB is that the hard clipping option is more of a hard edged dynamic sound due to the LED clipping rather then a subtle distortion.
It is also a tight-ish squeeze in a 1590BB enclosure. I will post some pictures in the appropriate thread.