I agree with your thoughts on the AN Duke. Another option might be to use a high-pass filter like Vandersteen uses, and then roll the subs up to match the rolled off frequency and output of the main AN speakers. Of course you may accomplish the same thing more simply by moving them out from the wall but the high pass would (theoretically) reduce the work required by the main amplifier.
BTW, I would like to hear your swarm system some day. Adding a second Aerial sub was a huge benefit to the sound of my system, in particular by better controlling bass in my room.
BTW, I would like to hear your swarm system some day. Adding a second Aerial sub was a huge benefit to the sound of my system, in particular by better controlling bass in my room.