Here is a verified layout of Foolton...ahem Fulltone Mas Malo which is a quite good sounding Big Muff variant. Input stage has a "Hot" control and the output stage is powered by a J Fet just like BJF Fire Red Fuzz.
I had some issues with fizz and oscillation with all pots dimed, swapped out trannies multiple times but no dice. I decided to tweak the Miller cap at the first clipping stage. With a 1,2nF cap the oscillation and most of the fizz was gone without altering the sound of the pedal.