Shocked. Need Opinions. How muck power do I need?

I don't know your specific components, but, as a general matter, a lot of people can do with far less power than they think they need.  But, there is no reason to go lower and lower just for the sake of seeing how low you can go.  With solid state, you can achieve fairly high power levels without that much additional cost, so there is less of a reason to go very low in power unless you are taking a fundamentally different approach to design (e.g., First Watt, an offshoot of Pass Labs).

It is a different story if you are looking at tube amps.  With tube amps, there is quite a bit more variability in sound quality and achieving higher power often comes at a sonic price.  That is why low power makes more sense, if you can live with the lower maximum volume level.  Most of my favorite tube amps are under 8 watts, although there are some that I like that hit the heady rating of 100 watts per channel.

Remember, all things being equal, you need ten times the power to double the sound volume. 

In my experience the PassLabs deliver super control of speakers such as the PMC Twenty26 vs like you found with the Evo, sounds a little weak with the PMC MB2SE. The ARC D240 MKII (120W per channel, fully differential) was much better able to deliver power.

Power supply. Power supply. Power supply. 
 

Bigger amps, have bigger power supplies. Depending on how loud you are listening, as has been said above, it’s about current driving the difficult parts of the speakers load. 
 

Smaller amp could work, if it has a power supply capable of delivering the goods…

Always have much more power then you need ,good rule of thumb 

for if playing loud you don’t want to be going into transformer saturation and distortion , they say in transients you can have 10 x the power for short burst 

in transients milliseconds ,the power supplies and. Ample capacitances is very important .150 8 ohms 300 at 4 ohms is a solid amplifier double down 

if it cannot come close then average at best performance .the output-devises  such as how many Mosfets per channel will dictate current delivery to complement the transformer size ,and filter capacitance. My Coda amp 3k transformer ,almost 100 k in filter capacitances ,and 20 15 amp Mosfets  per channel , 100 amp  capability .

it has dual 16 amp slow blow fuses on the back that says a lot about current delivery and 4 more fuses inside the unit.

if tube then calibrated different for the size ,quality of the power transformers  and chokes ,power supplies. from my experiences which is over 4 decades .