how do you gauge and judge "timing"?

PRat, Pace Rhythm and Timing.

Heavily promoted by Naim Audio, gets your foot tapping.

Loved or hated, sacrifices detail.  

Ahhh, yes... embedded in PRaT (I usually refer to it as Rhythm and Pace). I must admit when I sense PRaT, no part of that feels like timing to me. But, your right, there is it is.

Just as a comment on PRaT. It is probably one of the most important characteristics there is in music. It is what involves you emotionally and makes you tap your foot an sway. It is also one of the most difficult to sense and identify. This is because it isn’t a specific locatable sound quality. You can’t really point to a place in space at a sound and say, hear that... that is PRaT. It is a gestalt characteristic. It took me over thirty five years before I was able to identify it. Like a lot of parameters in music, once you hear it... then you can identify it consistent. 

When I think back in time, I can remember systems that had incredible PRaT... an how they impressed me... but couldn’t tell you why. Often the ones that displayed it the most were emotionally captivating but really lacked detail. When the balance is right with detail and PRaT... to my mind you have a really audiophile system... The thing that reproduces the whole experience. 

Anyway, don’t expect to just sit down and hear it. It often takes years to recognize it. I have sat with experienced audiophiles and helped coach them to hear it. 

One of the scenarios that have often had a huge amount of PRaT (live and in recordings) is really good drumming groups... typically African or South Pacific. all sorts of different drums simultaneous in perfect rhythm... hmm somewhere in there must be the timing thing.. 

time alignment of speaker’s drivers is an issue (not the speed of sound) the physical alignment of the drivers to each other, see the diagram

https://en.wikipedia.org/wiki/Loudspeaker_time_alignment

here, JSE (many others) slanted the face of their Model 2 Speakers

Here, I tilt my speakers back, it’s to aim the tweeter’s up for both time alignment and directivity of the tweeter to seated ear height

I put a 2x4 flat above the front wheels to tilt them back

Am currently experiencing this with a power cable upgrade on my Jay’s transport.  The new cable offers better detail/separation and a more balanced tonality (the old one had too much lower-mid/upper-bass emphasis) but I also experience it as "slower" than its predecessor.

What really confounds me -- I only notice this on some CDs!  It will come as no surprise to anyone that when I reached out to the  manufacturer they said that there is no accounting for such differences in terms of engineering; it’s purely a subjective perceptual phenomena.

With the new cable, my body is responding differently to the same music. I used to constantly "drum" along with music with my right hand on the arm of my listening chair. I couldn’t help it. Now, with the new cable, the "drumming impulse" has shifted to my right foot and I feel the rhythmic aspect more inside my body, as opposed to my hand. In fact, my hand no longer moves at all! 

As mentioned, some CDs do seem to "drag" a bit, as if the drummer didn’t get enough sleep before the performance/recording session. I’ve noticed this tends to occur with music at slower tempos. So perhaps the old cable was creating an impression that everything was faster than it is?  

I haven’t experienced anything like this, before and have no idea what might be causing it. It’s certainly not expectation bias. I never would’ve imagined such a thing was even possible. 

. In a broader sense, timing in acoustics relates to the duration of sounds and the time intervals between them, which are critical for clarity, intelligibility, and overall sound quality» 

"Timing" is an acoustics concepts , it can refer also to time domain analysis ...