Nevermind - I found the info about the -newuser thing.

For anyone else wondering: It's in the whatsnew.txt for version a46

I forgot that I hadn't upgraded yet and I found it in there. Looks like I need to wrap my values in "".

--- Mystic BBS v1.12 A45 2020/02/18 (Linux/64)
* Origin: Compufuck | Binghamton, NY | compufuck.xyz:2323 (77:1/142)