The way each amp handled the paired speakers was fairly evident too in that the sound was tight. Quick. Clean.Actually that is the result of bandwidth. Output impedance can play a role in how 'tight' the bass is (but quite often, 'tight' also implies that the speaker is over-damped in the bass; while that gets you 'tight' bass it also means there is a loss of definition as the woofer is not allowed to move as far as it should).
Harmonics and dynamics differ from one setup to another but the speed and pacing were taught and pronounced. IMO those attributes are the result of power.
The main thing you are looking for with your speakers is the ability of the amp to act as a voltage source. This is the idea that the amp can put out the same voltage regardless of the load impedance.
The thing is, the amp does not have to double power as impedance is cut in half at **full power**. This is why the CJ tube amp worked on the speakers- it does not have a lot of so-called 'current' yet could do the job just fine.
IOW, there are a lot more amps available to you that will do the job.