I need a box SKU added for each Shopify order. Fast turnaround

Hello, I need help with Shopify. For every order placed at my shopify store, I need an equivalent box size added to the order. For instance: Small order is placed, small box sku is automatically added to the order. I have 3 box variations that must align with 15 different products. All of this on an easy spreadsheet for reference. I also need to ensure that my third party warehouse can accept the order so a few tests would be helpful. Must be able to complete within 24 hours. Thank you!