No supports are necessary for the print. Layer height and infill all depend on strength desired. I printed with .2mm layer height and 10% infill. M4x10 bolts are used to attach sun gears and layers. Planet gears may take some fidgeting to get into place but stay well.

M4x10 Bolts - 4 for stacking ring gear, 3 for sun gears, 3 for crank, 3 for each layer

Easily adaptable for input or output.