I would create aPrimary Copy with 7 Days / 1 Cycle and a Secondary one Synchronous Secondary Copy with 28 Days / 4 Cycles. This will create a duplicate right away, and give additional protection. Due to DataDomain Dedup this shouldn't eat up to much additional space.
If you want to avoid the copy for the first couple of days you can set up "defer aux copy for x days", say set it to 6. Then it will prevent AuxCopy in the first days after the Backup was taken.
Be aware that 7 Days / 1 Cycle does mean that you will end up with up to 13 Backups on your primary Copy, since the first cycle will only age out once all incremental Backups are aged as well (assuming Full/Incr mix).
Hope that Helps