all i can suggest is what we used to do. don't rely on meters and leds to get your mix right. get out front and listen to the overall mix. start with the main vocal. the rule of thumb is that the closer to the source the louder you set your level. so take the lead vocal to the clipping point on the channel input then set the master volume to the volume you need for the vocal in the room. our lead guitarist used a long lead. he set the overall mix by visiting the mixer and the only time he needed to go back on stage was to sing his vocals and one of us could sort that out from the front balancing his vocal to the main vocal.

nine times out of ten the balanced mix was the same for most venues and once we made a note of it all we did was turn the master volume up and down. sometimes we needed different eqs, reverb and feedback filters but the master mix was quite consistent.

i'm sure you'll get lots of advice but use your ears not the meters and leds. of course it was a lot easier with a roadie and a mixing desk out front but most of the time we were on our own.