This was a massive war for me for a long time, DJ before and DJ after both would be so much louder, some times there would be a good sound engineer who would balance it out but was very rare. I used a TC electronics finalizer on my master for some time and this worked great but was too much to take with the rest of my gear. now I take my kick samples and master them in the box so they can compete with the DJ, then route my modular through the Akai force and eq all the unwanted stuff and add a little sidechain also, works great and very clean and loud
regarding the mono v stereo, I have a lot of samples using stereo space and even add a spreader on the modular, creates a lot of space in the mono region for the kick and also makes it sound massive, I dunno why people always associate mono with clubs, I have played in 1000's and always appreciate some crazy stereo ****.