I just finished building a Durham Crazy Horse which is a pretty gnarly fuzz. it can go from a pretty heavy overdrive to a gated, spitty heavy fuzz. after buiding it, I found that I actually liked it better running on 12 volts so I added a small daughterboard to convert 9V to 12V. the stock one runs on 9V but when you have the 'volts' control set at minimum (CCW) it barely works at all, but you can certainly build it woithout the 12V daughterboard if you want it completely stock.
here's the demo of the pedal:
https://www.youtube.com/watch?v=F2oC3_POYJYand here's the vero with the 12V converter: