After some thinking of how to arrange the training materials on this topic so that my readers would understand and learn it better, I decided to create a video course about these chords. Here it is: Seventh Chord Training. If you want to master these advanced chords, check it out. As it's usual with my programs, there are 2 weeks of bonus trainings included in the price.
NOTE: Members of Total Organist Premium and Premium Plus Memberships can take this course without any additional charge.