The only way to check if the design is good or not is to make a sample.

Then you can see if there is anything you need to change.

When you decide to ask paper packaging supplier to make a sample, the key is to ask them produce a sample follow all the finishing.

It may take some time but it can show you the detail, and you still have a chance to make some changes before starting the mass production. Once sample is confirmed, the mass production will be easier to follow the details and get the qualified paper boxes.