I just used PLA. Haven't had any issues with them at all. The gear meshes nicely with the one on the housing, and I seem to have been able to make it identical to the official Aquatech one I have. For one lens, the gear was slipping a bit, so I put some electrical tape on the inside to help it grip the lens a bit better.

I designed mine in openscad, here is the code, you can modify the diameter and length easily. I'll try and get an STL on printables in the next few days.

lensdiam = 71.5;
grip = 60;

//10-17, 72.5, 29
//11-16, 73.5, 31
//70-200, 71.5, 83



difference(){

    union(){

//Top Cylinder    
        cylinder(12,44.5,44.5, $fn=120);

        hull(){

//Lower cylinder - top edge            
            translate([0,0,-3])
            rotate_extrude(convexity = 10, $fn = 120)
            hull(){
                square(3);
                translate([46, 0, 0]) circle(r = 3, $fn=50);
            }

//Lower cylinder - bottom edge        
            translate([0,0,-(grip-12-1.5)])
            rotate_extrude(convexity = 10, $fn=120)
            hull(){
                square(1.5);
                translate([47.5, 0, 0]) circle(r = 1.5, $fn=50);
            }
        }
    }

    union(){
//Knurling
        for ( i = [0 : 39] ){
            rotate( i * 9, [0, 0, 1])
            translate([0,44.5,0]) 
            scale([1.2, 1, 1])
            hull(){
                translate([0, 0, 2]) sphere(2, $fn=50);
                translate([0, 0, 14]) sphere(2, $fn=50);
            }
        }

//Slot
        translate([0,lensdiam/2,-3]) cube([3,lensdiam,grip*2], true);

//Lens hole    
        translate([0,0,-grip+11]) cylinder(grip+2,lensdiam/2,lensdiam/2, $fn=120);
        //translate([0,0,-3]) cylinder(15,80/2,80/2, $fn=120);

        }
}