Oracle 11.2 restore DB to a specific point

I should execute following tasks: 1. test system and during test change Oracle data and Create New/Remove Old datafiles and tablespace. 2. at the end of test rollback to behviour before of point 1. I'm working on Oracle 11.2 on two different sites: on single instance configuration and another in DataGuard environment. To reach the scope I think following possibilities: 1) a- execute dump before starting. b- recreate manually datafiles/tablespaces and import data from dump at the end. 2) a- backup via RMAN all the DB. b- restore via RMAN the backup at the end. 3) a- create recovery-point. b- flashback at the end ....???? (I'm not sure about this chance with change on Datafiles and tablespace. What your opinion on it? Thanks, Ste