Considering how many of Smallville's costumes were just leather jackets, her look was pretty good in my opinion. But her hair makeup and costume in Supergirl were totally fire!
I mean that's not a bonus when the Smallville one was literally just a wig, frills, and a racoon face. A true achievement despite Smallville's limits would be something like Dr. Fate.
Honestly the only way I could tell back when watching was the fact that they are sorta on a Superman show so it narrows down the options. Plus whoever is sorta mainstream in his rogues gallery.