Sophie, I don't know if you've pulled the trigger on the Spatials yet, but I just saw this thread and wanted to share my experience. I have a pair of the Spatial Hologram M3 Turbo S speakers (not the newer Triode Masters). They're rated at 4 ohms, but have been reported to have a couple of 100-ohm peaks, one at 30 Hz and another around the 1-2 kHz range (see this thread -
https://www.audiocircle.com/index.php?topic=149584.140). I have the M3s paired with a Decware SE34I.5. Overall I'm happy with this combo, especially after tweaking things via tube rolling. However, my listening room is large enough that I wondered what more watts might give me.
Last fall I snagged a used Torii MkIV with the 4-8 ohm taps. To my surprise, the Torii-Spatial M3 combo was utterly disappointing. It sounded like an AM radio--weak bass and thin in the midrange. Since the speakers sound good with the SE34I.5, I gave Steve Deckert a call to get his thoughts. He doesn't have first-hand experience with Spatial speakers, but he indicated that it may just be a bad pairing, and said that the Zen triode amps are better at handling challenging loads. I didn't find the AudioCircle thread that I linked above until weeks later, but the location of the spikes in the graph in that thread correspond with the frequencies at which the Spatials sound anemic with the Torii.
I opted to try a different pair of speakers with the Torii rather than springing for the upgrade to the Spatial Triode Masters. I've tried Zu Omen Dirty Weekends (12 ohms) and Decware DM945s (6 ohms) with both of my Decware amps, and they both sound great considering the $1,000 price point of these speakers. For now, I'm keeping the SE34I.5 in my main listening room with the Spatials and the Torii in a second system with the DM945s. At some point I may replace the Spatials with something else, but open baffles sound better in my main room than any conventional speaker I've tried. YMMV--I'm dealing with some acoustical challenges in that room that are fairly unusual due to the architecture of the house.
Given that you already have a Torii and just need to find a set of speakers that are a good match for that amp, I'd stay away from the Spatial M3s, especially if you're buying used and will not be able to evaluate or return them. I'm not knocking Spatial speakers or the Torii at all. I'm happy with both the speakers and the amp--just not in the same system.

Dave