Interestingly when Herb Reichert reviewed the Rogue Stereo 100 he paired the amp with Harberth M30.2, KEF LS50, and Maggie .7 and liked them all...perhaps the Harbeth's best. He never once tried a higher impedance/high sensitivity speaker. Perhaps the peppy 100 watts obviated the need for a "traditional" tube-friendly speaker although he noted that the amp didn't seem any more powerful than his Pass XA25....in fact the Rogue seemed less alive, open, and dynamic. It would have been interesting if he had tried an 8 ohm/90+dB speaker to compare to the rest.
https://www.stereophile.com/content/rogue-audio-stereo-100-power-amplifier
https://www.stereophile.com/content/rogue-audio-stereo-100-power-amplifier