UPDATE:
After pushing the 4367s around for awhile with the powerful SS amps (AHB2's in MONO configuration) i decided to try some lower power tube amps.
First in was a pair of CAD-300SE. They are 300B SET with 11W output. I found that I must be much closer to the speakers and keep the volume way down. First impression was they do a lot of what the AHB2's do but quieter. Then I thought "I guess I don't care what those singers are saying - it sounds so beautiful." Then a mechanical transformer hum became annoying, especially since the volume is down and I had to sit so close. Also, the tube amps are much more finicky WRT line voltage. A Variac was pressed into service for regulation. These amps need 117V not the 121V which is more usual here.
Next I put in the ARC Ref 75SE. That was a bust. V3 flamed with a runaway bias. I called ARC service and they are so backlogged that can't take the unit for 5 months. I am on a waiting list for the repair. Go figure. At least it didn't fry a speaker.
Next was a single AHB2 and it just has a little less jump than the pair of AHB2's.
Next is 25W of glory in the form of a Luxman MQ-88uC. I LOVE, LOVE, LOVE it! It too needs the voltage down to 115V. Push Pull KT-88 in triode. Beautiful and relaxing sound on the JBL4367 with NO Fatigue! And just enough power to turn it up a bit.
On the way is a Pass Labs XA-25. I can't wait to hear how it plays with the big speakers.
As for reference level, Volumes equivalent to realistic levels are just to tiring though possible with these speakers and the AHB2's
So there you have it. I hope this is entertaining to some readers. It certainly is to me.