An Si fuzz with the right silicon trannys will clean up well.
A buffer before a fuzz unit tends to make it sound brittle, harsh, thin, overly bright, etc etc you get the idea.
Some people like an od before a fuzz, turns it into more distortion like - think cascading gain stages. Others do the fuzz into od, for a singing sustaining tone that is usually very smooth. Either one is up to you. I do the fuzz --> od way.
Check out the Subdecay Flying Tomato 2.0 for versatility, if you are not in the vintage camp.