Even if we had a test car and paved test track, I doubt I could do a very good job repeating a test like this. With the table, it's a closed loop system. A step in the right direction but still, not exact science as you put it.
FYI, the test board shown weight 18.97g. The little Brymen pocket meter weighs 78g. My Fluke 189, 545g.
The trimmer package on the test board seems to be the most commonly used from the meters I have looked at. The Mastech MS8264 appears to use the same package but the MS8211 used a different part. The Mastech I still have, MS8229, uses some larger plastic trimmers but it's a much older meter.
The trimmers appear only on the low end meters and the most common are the ones show, so maybe we can learn something from it. Like any rabbit hole, its just how deep we decide to go.