@qwerty123: The smallest diameter they make is 56mm. You could of course add something like foam rubber in between of course, but it's still far from ultimate. @soundgh2: Sorry, I think I didn't make myself clear, I already ordered from his lens gears for the 19s (though few other people make gears that are large enough for those), I meant that had I gone with 18s instead I would have been interested.
Think the problem on OCT18 is the focus part of the lens has 56 mm diameter so normal gears dont go small enough to grip the neck. You should be ok with the 19s though as they range from 83-95mm at the focus part of the lens
Looks like he has a solution for snap gear type rings that screw onto the OCT 18 lens body - just need enough ppl to be interested to make it worthwhile a run for him.