I think that I am in the D level, at least with the guitar and bass. I am in the C level with it comes to the wind controller and the keyboard.

I read music and have some music theory as does JonD. He is also in the D level when playing with others but he is in the E level when all alone at the keyboard. He was all alone for many years until we got together. When JonD and I get together we challenge each other with music theory as it applies to chords and chord progressions. They always come first in our compositions.

BobH is a fantastic finger picking guitarist who knows some chords but is at the A level when it comes to reading and music theory. Sometimes he just fingers chords that sound good in his songs and I have to figure out what they actually are, guitar wise that is.

You don't have to know how to read music or have any music theory to play well but it is a must when you have to figure out what you have played. YMMV

Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware