If you are starting from scratch, you may want to consider a tandem pedal. My suggestion is to get the Photon Phuzz and put it in front of the Zenith. It will overdrive the Zenith and bring out more of the characteristics you love.
I have done a zenith and really like it but thought it could use more gain. Taking inspiration from Barry, I decided to build a tandem pedal. It has a Photon Phuzz going into a Zenith into a Sho ‘Nuff. Lots of bluesy, transparent gain with no mud.