I'm sending you here so as not to derail the SEE announcement thread.
Since you asked about using it to its full potential,I can tell how I personally use it:
I'm a bit of a weird ass on my distorted presets ,as I cut almost completely the bass from the amp and really low values around 10% on the parametric EQ,and I focus my high end with an open weeper wah (the only one that does the job for me) at exactly 80%.Add to that I'm limited cause I own the HD300,and you got the reason why I grew so fond of these controls
I generally keep the master control cranked,the sag at values above half for tight amps and below half for loose amps ,the bias almost always at high values,and the bias-x around 28% (or generally below half) if the amp model needs some fine-tuning ease on the high end (supposing I've already EQ'd the high end the best i could) ,or above half if i need it tighter on the high end.On cleans I do the same,except for I usually keep the sag low.