Not sure if I am just repeating what has been said elsewhere, but just wanted to give my method of stopping the clamp from skipping on the lens as I have experienced a lot of slippage with the new clamp system too. I position the motor against the lens past its optimal gear tangent. I then tighten the rod clamp, very tight. Then I slide slowly the motor towards the gear tangent and as it moves it creates tension between the motor and the lense making it press itslef against the lens. I slide it until I cant move the motor anymore and then I tighten the Dovetail style clamp. This ensures the motor is pressed against the lense with all the force it can be based on how tight you tightened the original rod clamp. This for me has been the only way to avoid motor skippage. After a few tries you get very fast at it. Still this shouldnt be something we should be doing. I am looking at you Arri!