These are designed to attach to the wood beams of the loft bed I built my kid. The clips fit onto a 1.5 inch / 38mm width wood beam and the cupholder/bookholder slides into the clip(s). Feel free to edit the stl and widen to your needs.

The book holder dimensions

• d/w/h: 4.75 x 6.7 x 4.75 inch (120 x 170 x 120 mm)
• no supports needed
• prints in 2 parts: 1x bottom grate, 1x basket
• Needs 2 of the clips

cupholder

• diameter: 3.5 inches or 89 mm
• no supports needed
• prints in 1 part 1x cup holder
• Needs 1 of the clips

I don't think the layer height matters much. I used a .4mm nozzle with the .20 mm standard default Bambu studio profile.