Backup last 3 days

I'm using the new Backup system and I can set a daily backup for every day of the week, a weekly and monthly backup.
But there are any way to backup only the last X days?
I don't need a a 7 days backup the last 3 are  enough, my server is with lack of space to hold 7 daily backups + 1 weekly backup + 1 monthly backup.

I'm using the new Backup system and I can set a daily backup for every day of the week, a weekly and monthly backup.
But there are any way to backup only the last X days?
I don't need a a 7 days backup the last 3 are  enough, my server is with lack of space to hold 7 daily backups + 1 weekly backup + 1 monthly backup.

Can you not just choose three days of the week to back up, such as Mon, Wed, & Fri.

See "Custom Backup" for some ideas.