In order to follow danbooru's howto:romanize, she should be tagged hitou_nami. Maybe also add an alias to the current tag.
Updated by jxh2154
The problem with forcing the SZS characters into danbooru's romanization scheme is it kills the jokes.
Damn, I forgot about this homophonic stuff.
+1 for an alias then.
UPDATE: Actual name is Hitou (日塔 or ひとう), so alias should be -o -> -ou (according to howto:romanize). As for SZS name puns, I think they just should be mentioned in corresponding wiki entries.