This is simple-
A) If you adjust your system Limiters to Brick wall, and your amps are sized correctly, and have proper long term thermal protection in your rig, then you should be able to interface any Mixer. I just turn the attenuation knob on the DJM stuff almost down, so the Max volume can't clip- The Clip indicators on that console are pre-master attenuator, but the actual clipping occurs in the output stage. I tell em, one yellow, but find 'em in the red all the time.
On Rane Mixers, the headroom is expansive, so its tougher. There can be serious level being sent, so again, I setup a brick wall limiter at about +10dBu.
A&H- same, but again the clip meters are not indicative of clip. same treatment as the Ranes.
However, by far and wide, the best tactic is this:
Know the names of all the DJ's & talk to them. I introduce myself to everyone and let them know how the system is setup, where the clip points are, and what I may ask of them during the show. Very rarely, do I get one who insists on blasting, and if it's an issue, I just find the promoter and let him/her know what's happening. I never argue with the talent. If I get yelled at, I'll just tell them to get out of the booth, politely & firmly. Nad I'll turn a gig down if there are repeat incidents.
T