8 disks is not few disks. You may think you’re running a small risk, but you’re absolutely not.
Please read this: The Latest - Whether RAID 5 is still safe in 2019 - Digistor Australia
If you don’t want to read the entire article, here is the most important image.
With your setup in RAID5, you’re almost guaranteed to fail a rebuild.
Have enterprise level HDD’s with lower URE rates? The image does look better, but still not great at all.
It seems the P440 supports online RAID level migration. Do yourself a favor and use it.
The bandwidth setting is no longer active. It never really worked to begin with and it has now been deprecated. It doesn’t matter what you fill in there. It will be ignored.
DDNS on the router is the best method if your router supports it. You don’t have to install and run the DUC on your node machine if you use your router to update DDNS.