Well, I'm not an expert at setting up the unit myself - I probably don't know how to word things the 'proper' way.
That said.
I think what you need to watch out are 2 things:
1) Appropriate tone/sound for the setting you're playing in
2) Can you be heard?
So by (1), I mean, you might not want a boomy, bassy tone when playing in a large open hall. Maybe your guitar is overly bright sounding because of the fresh set of strings on it. Or perhaps you're going to be doing a more mellow, quiet set. Those situations require different settings no? Less bass. Less treble, a presence cut. More mids, reduced low end and a rounded off treble. You see what I mean?
By (2), I mean... no point having a great sounding tone thru the PA... only to be drowned out by the band. Sometimes, to sit well in the mix, you have to live with a tone that doesn't sound too nice on its own. E.g. you may need to up the presence or boost a certain frequency in order to be heard.