This isn't a min/max question, it's a how would this compare to other sets question, to do a fun thing for a char build.
For crit build there's a discussion when to use thief and when to use shadow mudus for crit chance or crit damage.
There's a set, twice-born star, which lets a char use two mundus stones so they could use thief and shadow.
If that wouldn't be less damage than other sets, we'd probably hear more about it, but roughly how would it compare?