Are you talking about your Tannoys (directional at low frequencies???) or your commercial product, the dipole? I was referring to the former, the latter I heard last week and found the bass to be eccentric.
Again, in a typically small UK living room, I would calculate that your solution will either cause time smear of mid bass transients or, as you say will result in the room nodes not being suppressed.
Are you familiar at all with the work of the Harman Group and the Bass Enhance program?