As far as drivers during my setup a year ago I did notice that the newest Nvidia drivers resulted in code 43 even with some common workarounds. I run 4 Nvidia cards on 4 VM's and each have been stable for over a year, I'm very happy and impressed at the stability.
The config that worked best for me was booting UnRaid in Legacy mode using the dumped vbios' for each VM and using an "older" Nvidia driver, the newest that I can confirm works stable for me is 399.24 but 388.13 or 368.81 also worked. Its fairly easy to dump the vbios using TechPowerUp GPU-Z but you may need to find an older version if it doesn't dump with the new version, also maybe try booting a standard machine with the card in windows, I remember it initially gave me errors when I tried to dump vbios from the VM. You will need to use a hex editor to remove the header in the vbios that is added by GPU-z via this method.
Hex Editor (HxD)
https://mh-nexus.de/en/hxd/
video for Hex modification (go to ~4min)
Nvidia Driver 399.24 (shouldn't be necessary)
https://www.nvidia.com/Download/driverResults.aspx/137727/en-us
This is what I have added in the xml for my VM regarding Hyper-V (for me lines 33-41)
<hyperv>
<relaxed state='on'/>
<vapic state='on'/>
<spinlocks state='on' retries='8191'/>
<vendor_id state='on' value='none'/>
</hyperv>
<kvm>
<hidden state='on'/>
</kvm>
##Helpful side note: If you want to passthrough a Hard Drive 'directly' instead of a vdisk...
Source: https://www.youtube.com/watch?v=QaB9HhpbDAI
UPDATE: I just found out that SpaceInvader uploaded a new video for this issue 2 months ago
If you specify the slot and multifunction mode in the XML like he did, with the other things mentioned; I can confirm driver 442.50 works with my GTX1060