Just pointing out that your lens gear is on your zoom ring. You may well want a gear on your zoom sometime, you can run a motor on it, old J4s are cheap now. I don't know how well you can zoom with that follow focus, I never did it, just used it for focus on primes.
Eventually, if you are patient or clever, you could have a decent 0.8 cine gear on focus and zoom rings. The iris ring has only about 6mm available space before you start obscuring the T stop numbers, so that's a bit trickier. I pulled my 10.4-52 from the cupboard for a look, the focus ring is a simple split gear with the clamp screw parallel to the ring tangent buried under the thread, a limited run factory item. These may still be around, cheap if you can find them.
There are some interesting modern options...there was a chap, selling on eBay, helicopter sean, making cheap gear rings that might be usefull, can't remember if they were CNC made, aluminum, or some higher resolution 3D print
(EDIT: factory item does not mean I imply it was made by cooke/arri. My guess is a third party)
Edited by Gregg MacPherson, 16 April 2017 - 07:03 PM.