I used Simplify 3D for slicing and manually placed supports under the extended arm only. The small gap that didn't have support bridged very well when I printed so ymmv. The layer height is somewhat arbitrary. I suspect it would print just fine anywhere between .2 and .35 layer height.
I designed in Fusion360. I had always wanted to try a print in place design and took the inspiration from the great Maker Faire Robot head rotation by LeFabShop that you can make out in the picture below. It's a rather simple hourglass shape with a .8mm clearance gap at the base and graduating down to a .5mm gap at the top to help a little with any first layer overage...