It's very difficult to give a good performance when you can't hear everything how you need/like it, I've done gigs where I got through because I new the songs note perfect, but you don't go off as well in those situations. I try to place my cab(s) so they open up on my ears (not my legs) or I end up too loud, but I also need to hear the rest of the band, and they me. So when I place us around a room, space, stage, I try to have it that we can all hear ourselves and each other (keeping in mind corners/floors that can couple and add boom/mud).
So just had an acoustic chat with my audio file mate... There's a sort of formula for this (bass boosts in rooms). So ideal (helpful) distances between things (to control (not antagonise) bass boost effects of rooms) a= distance from acoustic centre (measured from centre of cones) of cabs to floor (draw an X between the centre of the 4 12s of you L stack, is acoustic centre), b = acoustic centre to side wall, c = acoustic centre to rear wall. Ratio: a=1, b=1.5, c=2.25, but better is b=1.6 and c=2.4. It's dubbed the Allison effect, unequal path lengths.
Also to prevent box coupling, the distance between speaker cabs needs to be the same or more as the baffle size (the size of the cabs front (baffle)) When you stack 2 cabs, the baffle size doubles and give a bass boost depending on freq,~ 3db, 6 db, 12 db etc going down. To eq out (which is an option, start from 150hz and go down (depending how much eq control you have)). You could do a 150hz shelf, or if you have 3rd Octave, start with -3db at 150, -6 at 75hz, -12 at 37.5hz.
Padding the room and getting bass off the floor are good practical solutions.