0.3MM Layer Height (Or Higher Quality), 15% Infill, No-Brim (Or Raft), No Support.
Tip 1 : For Adults print at 100% scale, for children print at 80% scale. Don't print smaller than 80% Scale, as it affects the designed in clearances for the beads to flow smoothly.
Tip 2 : Slice at desired layer height, then plan the color swap equally from top and bottom by adding/subtracting the same number of layers on both sides.