This is a tutorial showing how David Gilmour uses overdrive and booster pedals in combination with his Big Muffs. The Coorsound Powerbooster is placed AFTER the Big Muff, set with a very subtle treble and gain boost. This adds a bit more presence and enhances the sustain and attack. Please take in account the compression added by uploading on YouTube.
See www.gilmourish.com and the Big Muff Tone Tutorial for an in depth tutorial and description of the tone and setup.