Sometimes you are looking for a dark tone, sometimes you are looking for a bright tone.
Some fuzz pedals have really wide range of tonal options. Maybe its because the signal is heavily distorted and there are tons of harmonics in the tone so the filtering that mass of fuzz can feel really wide and deep.
I like the darker sounds of fuzz, but it really depends on the amp you are using.
So there is no rules.
If it sounds good, it is good no matter the settings :)
And if you have a great tone, you are getting more inspired to write better music!
Or at least new music.
I think that fuzz pedals are most often the "writing" pedals.
That means to get the most out of your fuzz, you need to write music for it.
Go and write new music!
May the muse be with you!