We spent a great deal of time listening to the O/96s with single and parallel 300B SET amps and these did not have nearly enough power. The speakers opened up with about 30 watts plus and decided that the best sound came from a pair of 60W OTL monos.
I am convinced that the lower wattage went into a very soft clip quickly that actually made the sound a bit larger than normal. The sound thickened. So I (we) felt that actually the lower powered amps gave some perhaps more of what they liked but this certainly did not do justice to the source. So in my experience, the worst amp for these speakers were push pull designs followed by the lowered power single ended. The speakers were best served by a more neutral tube amp of higher power that wasnt a push pull type.
Hours of direct comparison were needed to really sort this out. Most of this was done on the O/96s and some on the O/93s. The only components changed were the amplifiers. These sessions were extremely valuable and really elevated our listening acumen. Of course it also ruined about 10 songs due to overexposure.
With these speakers, the only type of single ended design I would consider would be an 845 or 211 type. There is no denying the quality of single ended midrange, but I tend to like these amps when paired with a less "meaty" sounding speaker. Perhaps too much of a good thing.