There are a lot of versions and subversions of the Big Muff. Many consider the Violet Ram’s Head to be the best, though many consider the Triangle, or IC, or Green Russian, etc. the best. YMMV
This one has the pots hard mounted to the board, though depending on the enclosure you use, it may be best to wire them off-board. This layout is heavily inspired by the original Ram’s Head circuit board, just resized for more typical sized components. I’ve also added a polarity protection diode, power filtering cap, and an LED resistor.
EHX also used this same circuit for the Guild Foxey Lady (3-knob) as well as several other OEM pedals EHX produced.