I would like more granular control over the packaging sizes. We use a whole range of packaging from polythene mailing bags, bubble bags to double-wall cardboard boxes. That said, not all these packaging materials are suitable for all items.

An idea to achieve this could be packaging groups. These groups are their own list of packaging sizes which can be assigned to a product to restrict the packaging size progression to a set of packaging materials.

This way when multiples of an item are ordered we can choose the exact packaging sizes it must follow. For example, we can restrict a product to only move up in sizes of boxes and another product to only move up in sizes of bubble lined bags.

In the instance of a multi-line order where there are conflicting or more than one packaging size which matches, then an option to prioritize a packaging group should be available.

An alternate way to achieve the above would be being able to enable or disable a packaging size for each product. This way I can disable the packaging sizes for mailing bags on items I only want to go up in size of boxes.

Bag1 (Size 1) - Disabled
Box1 (Size 1) - Enabled
Bag2 (Size 2) - Disabled
Box2 (Size 2) - Enabled

In the event of a multi-line order if both products have a matching packaging size enabled that fits it just works. If not then the selected priority would be selected.