I took an interior repair course from Ding King. It was a very disappointing experience. The guy who taught the course was a dent man.
He also taught the detail course, interior repair course, and what ever else they offered. I spent a lot of money on very little training. I wont go into a lot of detail, but I will tell you the guy never worked a day in his life in the field as an interior repair guy.
Don't waste your money on Ding King. Find a detailer to teach you. Work for free for him if you have to. You'll end up spending a lot less money and getting a much better education.
Tony