Recommend a y-cable and drive the subs with the Node's sub output. The issue with some subs running from high level (speaker) outputs is that many assume the amp is single ended, which is not the case for many Class-D amps, including Maraschino Cherry, MEGAschino, and x-CHerry (they have balanced outputs, aka "BTL" or bridge-tied-load). It's easy enough to design a true differential high level input for subs, so I could never understand this limitation.
Either way, it's more of a "purest approach" to separate the lows from the highs for this. Replacement bass is better than supplemental bass because it lowers excursion of the full range speakers, which lowers distortion.