How to tell the current from the amp

Just trying to be more scientific and objective here.

Good luck with that. With solid state, if an amp doubles its power at 4 ohms and can handle low impedances, no worries. On the tube amp side, tube amps usually have current reserves to run the vacuum tubes but not always. 

The idea is that a high current amp will perform consistently well even as your speaker impedance changes.  If your speaker impedance is stable, or high enough this becomes pretty irrelevant. Sometimes you might even like the combination of a low current amp and low impedance speaker if the dips happen where you like or need them to.

The general first thing to look for is that the current doubles as impedance halves:

8 Ohms:  100 Watts

4 Ohms: 200 Watts

2 Ohms:  400 Watts

Another thing to look for is being rated to drive 2 Ohm loads. 

But unless you have unusually difficult to drive speakers this isn't usually a problem for most good solid state amplifiers. Electrostatic speakers are a notable "always a problem" speakers. :)

Most amplifiers are voltage devices that provide voltage gain and voltage based feedback.

The idea that they shove current out in a massive burst is not going to happen unless the speaker’s impedance is headed towards zero.

You may want to provide the impedance curve for your speakers?

I get the case where you have double the wattage with half the impedance, but such case only show the device is qualified as high current, but now by how high as a quantifiable measurement. It’s only a relative measurement. So there is no one measurement available to indicate the “current” capability? I don’t have electrical technical back, and I feel this concept is being mystified…