My sort of era... 1993 Golf Clipper - so proper special that one
Actually was wondering if you could take some readings over time... assuming it fits in with your routine, but...
What, if anything, does claying take off?
What does polishing take off?
After those, does waxing register anything as a + or would the gauge go though it?
All of the above assumes that the gauge has a suitable number of decimals!
The BMW paint seems to be quite soft - how easily it swirls** - be interesting to see how does this compare to the VWs?
** Yeah I know that'll be my poor technique, but that same poor technique didn't have as bad an affect on my old Peugeot years ago!