equalizer on board

[francoran]

I know that many of you have their own mixer/equalizer for their keyboards in the live set. I use to bring just the JS, so I don't really need a mixer only for me, but sometimes I miss a good equalizer, even though the one on the panel is not so bad.
I would like to know how do you employ it, if you miss the medium knob and if you leave the setting of the two knobs (high and low) at the same level during all the concert or you change it according with the patch that you are playing. We all know, for example, that enhancing high frequencies could be useful for a piano sound to cut the mix, but in the meantime it would be awful for strings or brass. So, do you ever tweak the two knobs or you prefer to leave them at a flat level or thereabout? Another question is if I want to cut or at least attenuate medium frequencies on the fly, is it possible just with the two knobs high and low?