Database Software

Hi,

i am interested in setting up automatic deletion of backups on disk, after copied to tape.
level 0 full backup done end of week and incrementals done daily.
i want to delete incrementals on disk that were taken before 7 days , i.e before the last level 0

should i use:
run{
DELETE BACKUP COMPLETED BEFORE 'SYSDATE-7' DEVICE TYPE DISK;
DELETE ARCHIVELOG UNTIL TIME 'SYSDATE-7';
BACKUP INCREMENTAL LEVEL 1 CUMULATIVE DATABASE FILESPERSET 4 PLUS ARCHIVELOG;
}

or should i do it this way:

run{
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS
CROSSCHECK BACKUP;
DELETE OBSOLETE;
BACKUP INCREMENTAL LEVEL 1 CUMULATIVE DATABASE FILESPERSET 4 PLUS ARCHIVELOG;
}

which is oracle recommended? or will both work?

thanks