• Material: PLA, PETG 
• Nozzle: 0.4 mm 
• Layer height: 0.15 - 0.20mm
• Infill Density:  20%  this is fine for strength but if you want a yo-yo that has more weight you can up the infill to your liking
• Wall Thickness: 2.0
• Supports: No
• Build Plate Adhesion: None

It should fit together fairly snug but if you are worried about it coming apart you can add a drop of super glue before forcing them together.