"The basic question is: from a specification standpoint which speaker pairs up with the Stellar 300 best?"
The question was not what amplifier(s) best suits these speakers. The question was which of the two speakers best suits the amplifier. As mentioned earlier, given the similarities between the two speakers’ specifications, you’d just need to listen to both and compare the two in your room and decide which one sounds better to YOU. I haven’t heard the Quads but if the Focal 926 sounds anywhere near what 936 sounds like, I’d guess you’ll like them better. Given that you have them all in your home, this appears to be a no brainer approach. Let us know how you make out.
The question was not what amplifier(s) best suits these speakers. The question was which of the two speakers best suits the amplifier. As mentioned earlier, given the similarities between the two speakers’ specifications, you’d just need to listen to both and compare the two in your room and decide which one sounds better to YOU. I haven’t heard the Quads but if the Focal 926 sounds anywhere near what 936 sounds like, I’d guess you’ll like them better. Given that you have them all in your home, this appears to be a no brainer approach. Let us know how you make out.