Each one of my products = (1) Package.
I have several Package Sets simply saved as 1 Box, 2 Boxes, 5 Boxes, 10 Boxes, 25 Boxes, etc.
If ShipStation could expose "Apply Package Set" to its list of available Bulk Actions, then you could sort your Shipping Queue by Quantity and configure multiple packages across multiple orders en masse.
Mark Edginton Peak Health commented
Another idea would be to have the ability to add saved "Package Sets" to "Packages" so they could be utilized in automation rules.