My 1600 Watt 18″ sub is usually set to -6dB sensitivity to keep some balance in the total sound. So I don’t bother with corner loading or such :-), the setup is slightly bass heavy as is. I have it sit either next to the DJ stand (left or right whichever works best in the venue I am in) or off to one side, with the top speaker sitting on top of it and the other top speaker on a speaker stand the same distance on the other side.
One thing done a lot in PA work is if you have multiple subs, is to turn one around (i.e. facing back). This cancels out a part of the bass being felt behind the subs and adds a bit to the bass being felt in front (sort of a trick to get some directionality in the low end). This only works if they are stacked on top or tight against each other though, not when one is in one corner of the room and the next one in the other corner.
Just my two cents.
Greetinx,
C.