In your size room, 250.5 is more than enough ! It seems that you listen almost entire time in class A. One small secret between audiophiles is that 250.5 is the best sounding Pass! Just to let you know ! Keep it – 350.5 will bring you nothing new !
For all other SLOG members – the difference between Pass 350.5 and JC-1s :
Pass: better midrange – so sax, voices, etc is much more natural, entire sound is more tube like …
JC-1s – better frequency extension , more dynamic and tighter bass
What do I prefer ? Pass. Sound more like a real life .. some people would like JC-1s… they would say it is more neutral .. I agree..
It is old story that Atma and CAT are good with SL … it used to be Wolcott in the past .. I never heard them on the SL so I do not know but I could bet they are good because many people love that combo.
On other side I heard these amps with other speakers and I did not like them. But it means nothing! Different systems, my tastes , your tastes, etc… What I want to say is – do not believe nobody until you hear it by your own ears and in your system !