The dual woofer system you propoose is interesting though, in that it lets you retain all the benefits of DI matching and gain additinal benefits of adding bass sound sources. That's always a good thing. The way I would implement it is to keep the original physical relationships of midwoofer to tweeter, both in position and crossover, and add to that a second woofer below the first with a simple first-order crossover around 150Hz. This would provide two bass sound sources and would also allow the midwoofer to be higher, closer to ear level, without introducing a floor reflection cancellation notch in the midbass. The pair of woofers operarating together below 200Hz would reduce floor bounce and room modes, and crossover to the single midwoofer above the modal range would allow it to function as a point source up to the DI matching range, where crossover to the tweeter would be done as it is in the existing design.