@soix A speaker level connection with the SVS and NHT would be difficult. I'm currently sending the LFE channel to the SVS via a REL wireless transmitter. And, I don't really have a great spot for the NHT. It would be interesting to try four subs, though.
It's a shame to not use the NHT. It's a nice subwoofer. I could swap it for the SVS, but the SVS is probably better for movies. The NHT has two drivers in a sealed enclosure with an outboard controller. I had NHT replace the capacitors and they also replaced the tracking voltage controls a couple of years ago. They were very helpful and reasonable about costs. I think I paid $150 for the repair..