buy a driverack pa+ and a RTA mic. plug it into the drive rack run the auto EQ wizard, and save it.
its not SUPER perfecto, however its totally usable. the other plus side is that you can always recall it from venue to venue...save time on the repeat visits.
we use a Driverack PA in our system and never have a problem with feedback..
we get complements on our sound from a lot of people that are in the industry, we once did a gig alternating sets with another band (we are good friends with the other band) at a local club and had two sound systems setup, ours and theirs, they hire a sound company to do their sound and we were told all night long that our sound was way better than theirs! even the band members from the other band said the same thing! LOL!
We swear on the Driverack PA.. it does everything!