The StudioLive AIR 12 and AIR 18s has a peak amperage of:
AR 12 = 3.5 A
AR 18 = 5.3 A
To run all of your speakers, you are looking at the following amperage draw at full tilt:
AIR12 max Amp 3.5 X 5 = 17.5A
AIR18 max Amp 5.3 X 2 = 10.6A
My suggestion is to separate the two systems with two different breakers, that really just need to be 20 amps each. That will give you the ability to run both of your Left and Right front of house speakers (17.6 A full tilt) and your Monitors (10/5 A full tilt) with enough power separating the two, with room to spare on stage.