Export a new id in the middle of a song keeping diskspace

[Grace de Richebourg]

Lets say i am in the middle of a song and i find a very good idea for a new song.
I want to quickly export it as a new folder but considering i just need those few tracks only between measure 5 and 6 for example, whats the most fast and efficient process to export the file only with the material used in the id please ? (in view to keep diskspace)
(i thought the pool feature "used filed" only would make the deal but no....)

 

[Grace de Richebourg]

(Little aside, you import song datas from song arrangment page A to song arrangment page B but then you rename song arrangment A, question; will S1 recognise the update and will still be able to open B without giving me a missing audio panel please ?)