I am really surprised this is not an available action to have applied when processing automation rules.
This would be a work around to the issue of not being able to use a decimal when having an automation rule "Set package dimensions"
There is currently no way to automate the settings from the "Preset Groups" to specific Products. This basically means each time an order is placed for a product that hasn't previously been assigned with a "Preset Group", you need to manually assign it. This completely defeats the point of setting up the system for automation purposes.
This could be resolved in multiple ways, but here is my suggestions...
Automation rules for products could be included which allow us to "Tag" the products based on custom data, such as "Category" or "Title Content Includes" for example. Then "Preset Groups" could be automatically applied based on these "Tags".