Tower,
I had a friend named Philip Churchill. He was a wonderful person, and a great knapper. He was arguably the best Danish dagger replicator in the world. He was very excited about my research, because he saw that I had put together a body of evidence that no one had ever seen, or seriously looked at before.
Anyway, Philip was a pro. He could make anything. And, when he decided to learn "freehand indirect percussion", he was able to learn in a short ninety hours. Ninety hours of practice equates to three hours of practice per day, for one month. And, he was a flintknapping wizard.
Philip was lucky because he could look at my videos and use what he saw to help correct and modify what he was doing. In my case, there was no one, save the story of some obscure indian flintknappers in Central America. So, in my case, I think it took about six months of practice - and inventing everything - before my skills began to level out.
So, my feeling is that if a person can learn in under six months - or ninety hours - the person will be doing fine. The barrier that people seem to have today is that uninformed flintknappers are often told about "KISS" - "keep it simple, stupid".
Well, we do not have a right to say that ancient flintknapping qualified as KISS. Beyond that, ancient people used flaking tools that we still do not understand - even after decades of modern flintknapping. So, in order for people to learn, and to understand, they will have to break past the mental barriers that have been erected. We don't have a right to make what ancient people did conform to our own ideas. The world is bigger than that, much bigger.
January of 2017 will mark the second anniversary of when I first understood how to create overshot with a common deer tine. So far, all of the followers of "KISS" have not been able to figure it out, though I have shown them the tools, and the results. And, I would not have figured it out, myself, if I had not come to understand something written a long time ago. And, what I came to understand does not qualify as "KISS". But, it sure works great.
So far, I have been showing the Flint Flaker method for six months. And, I do not know whether anyone has yet learned. Hopefully, people will break past the barriers.