HAMMER, disk mirroring and secure NFS

[Andrea]

Hi everybody. I'm in the process of migrating my work and hobby 
activities to DragonFlyBSD. I'm very happy with it but I have four 
questions I can't find answers to. I hope someone with more experience 
can help me with some of them.

1) On my main PC I'm planning to install DragonFlyBSD on a small SSD and 
use two 6TB disks for my home directory: one disk for the master PFS, 
one as a copy with HAMMER's mirror feature.
I have a 7200 rpm Seagate IronWolf and a 5400 rpm Western Digital Red. 
Can I use them together or HAMMER's mirror feature requires (or work 
best with) identical disks (or disks from different brands but same 
speed)? If I can use them do you suggest using the faster disk for the 
master or the mirror?

2) If I understand correctly HAMMER doesn't provide auto-healing like 
ZFS but is able to identify data corruption, allowing to manually 
restore problematic file from the mirror, snapshots or backups. So it 
can provide same (or better) level of data safety of ZFS. Can you 
confirm my understanding is right?

3) I'd like to backup my home directory on an external USB disk. I would 
like to use HAMMER's mirror feature for this task too. Does it make 
sense or mirroring should be used only for continuous synchronization 
and something like rsync is better for daily backups on large external HDDs?

4) A second PC will need to access my home directory. This second PC 
will use FreeBSD at first but I'll switch it to DragonFlyBSD too once 
all of my work will have been ported from FreeBSD to DragonFlyBSD.
I'd like to use NFS but I'm concerned about security: I'm in my home 
network but I don't trust everything on it (the tablet of a guest as an 
example). Have you got any advice on how to secure NFS on DragonFlyBSD?
If I understand correctly exporting an HAMMER pool with NFS doesn't 
provide encryption or authentication "out of the box". I found many 
guides about using Kerberos, IPSec, or SSH tunnels. What should I try 
first? Or I'm simply paranoid and using plain NFS on a home network is 
the way to go?

Thanks to everybody who took the time to read it! I really like 
DragonFlyBSD, I hope to be able to use it as my main OS as soon as possible!

Andrea