I followed geekazoid's instructions and they worked like a charm! From a Windows box, that is. However, I now can't connect to those same shares from a Linux (Mint 19) machine using Samba and I think I've tried every combination of username, domain, workgroup. Anyone have any recommendations? I don't think this is an Unraid-specific issue but I also haven't been able to find much information about it elsewhere.
I'm also running into the Unassigned Devices Samba share issue like everyone else but not going to worry about that for the time being.