Shopify app for custom products

Rebuilding a website which has a bunch of conditonal logic into Shopify. Need a custom app to support different required minimum sizes etc for different varrients. Want to be able to display example photos for each product as well.

Current site can be seen here with the single product with variants - https://www.custombox.co.nz/design-and-quote/

Minimum sizes etc can be seen here - https://www.custombox.co.nz/box-styles/