3D-Printed Fruit Transport Box

I need a solid, printable design for a medium-sized box—roughly 20 × 20 × 20 cm—built specifically to protect fresh custard apples while they travel from farm to market. The focus is impact resistance and gentle ventilation, not retail display, so the walls can be functional rather than decorative as long as the fruit arrives bruise-free.

Here is what will make the file a success for me:
• Internal geometry that cradles several custard apples without squeezing them, ideally with removable inserts so I can adjust for different counts and sizes.
• Vent holes or ribs that keep air flowing yet still maintain overall strength.
• Lid and base that lock securely but open quickly—snap-fit, twist-lock or another tool-free solution would be perfect.
• Stackable corners or feet so multiple boxes stay stable in a van.
• Ready-to-print STL (or STEP) plus the native CAD file from SolidWorks, Fusion 360, or comparable software to allow tweaks later.

I’m looking to move fast—please let me know you can start right away and give me an estimate of how soon you can deliver the first draft for review.