This is a body reference from 3BA that i quickly made to easily convert outfits from FO4 to SE
Basically, i added a slider that matches the arms position
The reference is 3BA, but i guess it could work with unp since only the arms need to change position, i haven't tested
Text in the file to explain how it works
Rely on the screenshots in the file if you're having a hard time doing it, the order is indicated with the numbers in the text
Eh...