Hi Rene,
All interesting and great that you’re achieving your goals. After 40 years off that’s some achievement.

Using meters and gauges all very interesting, but I wonder if you’re using your eyes more than your ears in investigating your challenges? Greg’s “eyes closed” is so important I find, in learning both whats working and how its working, that for me I’d find watching meters a hindrance (except as a bit of fun of course). If you’re not sure of a pitch then a keyboard app will help you get the sound in your head/ears.

Good luck and hope the above doesn’t appear at all facetious. Its so hard on these forums to get a picture of where people are in their musical development. Also I’ll note that even if you only ever play with dots (i.e. no improv) being able to hear & sing a written line is so important and helps pretty much every aspect of your playing.

Paul.