Just a quick intro on the Cool-Lux Lux Gears. These can be added over the focus ring if you're working with non-cine lenses and have to use a follow focus system. It's a flexible material that is still firm enough to where it won't slip under your FF. They make a variety of sizes so that they can fit perfectly with your lens.
They have a basic Lens Compatibility Chart showing which Lux Gear should work with most popular lenses. But if you can't find your lens on the chart, you can also print out a ruler (on their website) that will let you measure your lens and select a proper size. You can check out the Cool-Lux Lux Gears following the link (here).