I believe Lee is asking about a single sub run stereo by having each coil receive a signal as opposed to both coils driven with the same signal and not having two subs.
I've only used a single sub for LFE so typically it's been a Y-splitter to feed both voice coils. For music I've always used one sub per channel. As such I have little idea between the differences between a single sub run stereo vs mono. Bass heavy instruments are usually panned to the center so my guess would be that there wouldn't be much difference when it comes to music.
I have a combination music/HT system. I am asking about using two (2) JL Audio subwoofers ( which I already own ) and hooking them up so that each sub plays the low bass of one stereo channel. So, there is a subwoofer for the left channel and a subwoofer for the right channel. In Home Theater use, they will both play the LFE channel if I simply select "no subwoofer" in the system setup. LFE is redirected to the mains if no subwoofer is chosen. Since I have two pairs of main outputs on the pre/pro, this is not a difficult setup choice. The level and phase adjustments will take a bit of work, but I will do it if it could provide a benefit.
At this point, it seems like an experiment worth trying. I'd still be interested in other opinions!
Lee