There’s a great article form Richard Sleigh in the latest issue of Harmonica World magazine on the music notation used by David Barrett in his teaching material at bluesharmonica.com. I completely agree with the sentiment. At first I was reluctant too. The whole thing appears arcane and unappealing but a little bit of effort pays off in spades.
I use the same material in my sessions and can’t recommend it highly enough. I can help and support you through the process if you want. Drop me a line. (Click images for larger version.)