I recommend setting your slicer to print the upper and lower bodies solid.
Remember these are large case halves, be sure to let them cool completely before removing them from the build plate. (They can warp)

The balls print well at 20% infill. I found that they print very nicely at lower print speeds.
You will need 14 balls of each color (Total of 28 balls needed)

9 rods needed

Use 2 pieces of 1.75mm Filament for the hinge pins.