Did you ever get a clear answer as to what Yaw Endpoint does? Since "Endpoint" is the final stage of something, I was assuming Yaw Endpoint means you can control the rate at which the spin or yaw comes to a stop. It seems the slowest stop would be 100% and fastest would be 150%. I guess the only way to know for sure is to test it out and see what it does, but it does seem strange that when you Google the term, you can't really find a clear definition for it and the question you initially posed is the first thing that shows up on Google!! Most people know what Yaw is, but it is the term "Endpoint" that is not super clear.