Possible to: Copy/Paste all javascript (& xml) from one pdf to another?

I have a suite of similar forms that require updates periodically. They have scripts for field actions as well as calculation and validation scripts. 

What is the best-practice here? I'd like to avoid manually copying the field action scripts into each field. The solution in my mind SHOULD BE a single javascript code pasted in a single place. i.e. in All Javascripts.

I've tried copy/pasting all scripts from the All Javascripts / JavaScript Editor into that of a new file, which has the same field names. However, nothing happens. 

I've attempted using Organize Pages to replace the file with javascripts with an updated file (from InDesign). But that doesn't work either: Acrobat chops up the design of both documents and distributes the elements (seemingly) randomly as layers, while also not including new/different design elements. 

I've also attempted to write all javascripts into a single hidden calculation field. My java experience is limited, but already I question whether this would be best-practice anyway. 

Any recommendations are appreciated.