Smiley faces

The parties in this drama are the owner of a small PA system, loaned to a local club, a friend recently "trained" by the owner to run the system and thus #1 sound man, and me, who had studied the manual and experimented with the system for months before my friend and the owner got involved. It's an amateur situation, so my "demotion" to #2 is only an annoyance, not a career problem. What's important is the sound itself.

The owner insists that the graphic EQs (one for the mains, another for the monitors) should be set to, and remain, a "smiley face," with the curve up about 6 to 10 DB at each end, and #1 insists on complying. That works more-or-less for the mains, but the monitors are very prone to feedback: vocal mics like to squeal with feedback at the high end of the smiley face, and guitars like to boom with feedback at the low end. So I think the "smiley face" EQ for the monitors is just wrong, but the owner has never actually come around in the evening to listen.

The owner and #1 insist the solution to the feedback is to use the channel EQs to compensate for the smiley face: every guitar channel should have the bass turned down, and every vocal channel should have the treble turned down. I think that just gives us two EQs fighting each other in unknown ways, and messes with the main mix to fix the monitor feedback. Absent proper measurement to tune the graphic EQs to the speakers in the room, I think (after a lot of tweaking) that the main graphic EQs should be started out flat, then tweaked a bit by ear, each channel's EQ should be adjusted to sound good in the mains, and the monitor graphic EQ should be adjusted to minimize feedback (a bit of a frown) at some cost to how good the monitors sound.. Is there a right and wrong here? Or is it just opinions?

Another problem is that the #1 sound man likes to record off the main mix, and thinks that once the sound check is done the mix shouldn't be touched, since changing things ruins his recording. I think that in an open mic and jam session context the mix needs constant tweaking as players and singers come and go, and if he wants to record he should bring in his own mixer and use the channel inserts -- then he can have a recording mix that is independent of the house mix. Again, is there a right and wrong here?