IMO Gradys sytem is the easiest to implement, and the most accurate I have come across. About the only thing I have no experience with, is the Zero X stuff from Tor Lowery , Everything of his is high level so I'm sure the kicking is also. I feel I kick as well as I will ever need to , so my time is better spent on other parts of my game.
Thank you for the information Billy. I happen to have Tor Lowry's banking and kicking videos. Will have a look and make a post when the time permits.