Small or large sub for music

When I first purchased my Wilson Max II’s and was talking about adding a new sub, someone on this forum laughed asking why I would even want a sub, using the Wilsons.  I purchased one JL Fathom 113 and it was great.  I then added a second one, placed in the opposite corner diagonally facing each other and it really smoothed out the response.  I use a DBX subharmonic sythesizer, along with a Sony  TA-E2000ESD, as a separate remote volume control.  The Sony has a parametric eq that I filter down the 50-60 hz frequencies and turn my crossover point on the subs, as low as it will go. I come out of my line stage’s tape monitor output, so I can isolate the bass.  Because the Sony has a motorized dial volume, I can pretty much tell, where to set it on the clock dial.  When I turn my main speakers off, just to hear the bass level, most of the time the bass is at a fairly low level and is not overpowering.  I get an almost seamless contribution from my subs.  I can also turn my subs off, to hear what it sounds like, without the subs.  The difference is almost always very subtle, but can hear a definite improvement with the subs.  I built some hefty stands, 18” tall with metal castors, so I can easily roll them around the room, to establish the best position. I think the trick, is to set your sub volume, as to not make them shake the room.  They’re like a quartet, each contributing, but none overpowering the other. They definitely have their place in my system.