I haven’t used those specifically, but have a set of EVs that are similar. It is a situation that needs more or less standard gain staging. The prinicple is to have the mixer operating at its most optimum, and have the amp/speakers also at a comfortable level, gain-wise. If you have the chance to run signal and do a test, it will be easier than trying to do it on the fly in a concert situations (Play back a Q-Drive recording, if you can.)
With the amps turned down, set up a mix so that you have decent comfortable levels on the output meters, so that you see some yallow but no red. Then bring up the speaker level to where you need it in the room, or perhaps just a bit louder than you plan to run the show, and then lower the main output masters to make it sound great but not too loud.
Then look at the controls on the speakers – if all is good you should find them abotu half way up. Mark them or put tape over the knobs so they don’t get bumped in transit, and you should be good to go!
In my systems for years, I usualy run separate amps all the way up, and powered speakers set at exactly half way up, and it always works out for me with the mixer meters just occasionally showing yellow, except with really loud groups where it get really close to the red – but you are asking for distortion if you run up that hot very much!
Hope you get some other responses too, as there are different ways of doing these things. Best luck!
L