Never been to a formal training like that but I've seen a ton of videos of correct notching techniques. I would be extremely interested in attending one of those chainsaw training classes if the focus of the class was notching one giant tree with maybe some mock circumstances. Obviously you don't just want to drop any big tree and it would be difficult to find one but I feel that would be worth coming to see compared to a straight stem that you could wrap your arms around. Art and science of practical rigging dvd series had a large one dropped and it really gave me insight watching something big come over.