op
if you are seriously considering new speakers to replace your chapmans, and use the 300b amp to drive i would suggest the following:
spatial audio (some models in the 93-94 db range w >8 ohm impedance - just stay away from their 4 ohm models)
omega line
higher klipsch’s as you have identified, and their brit relatives - tannoys
audio notes, quite expensive, but considered to be absolutely wonderful
it is difficult to do so presently, but i feel that with very high efficiency speakers, proper audition is very important as the sound signatures can be very distinct...