Your research may or may not be right, usually a lot of abuse occurs at the youth age, so in order to avoid it, with parents and coaches still pushing kids (as per above), don't pitch until the arm is maire mature
I still remain with with my opinion as to beginning later in pitching (delaying throwing off of the mound actually), tossing has nothing to do with it, we'll see how your theories holds up as your son gets older. That's the only way you will know if what you did or didn't do was the right thing or not. I am not talking about the obvious signals, because you have no idea what is actually going on inside.