Doubts about catalog

A new backup will not replace the previous backup - it will write a new backup each time a backup is done.

So, a new DR-file and new IMG and INFO files will be written for each backup.
I doubt that you have enough space on your F-drive to write a backup every week and keep that forever!

As I've said before - backups to DSU works the same way as tape.
Only when previous backups have expired can existing backups be overwritten.
Please read up on Disk Staging in Admin Guide I to stage catalog backups to tape.

You are also missing a FULL schedule in the policy.
A 'Cummulative Incr' will backup everything that has changed since the last Full backup in this policy.

A catalog backup once a week is not enough - if you are doing backups every day, you need to take a Catalog backup every day.

Infinity retention is way too much - what good will catalog backup be even within a month from now?

For DR, you need the latest Full and last Cummulative incremental along with DR-files.