I usually end up using EX P White Dizzy, since that is the costume input I use for a number of other characters like Slayer and Ky and it's become a habit, plus I've noticed that most characters get at least a decent color set for that so it's a safe choice when I can't remember specific ones. Sometimes I also use gold Dizzy (not GOLD gold), red/black goth Dizzy, and Easter Dizzy with the pale green/blue/yellow colors.
You would think that by now I would have her colors memorized, but I guess I don't usually care which colors I get aside from EX P Slayer, Reload K Faust, and Reload S ghost Potemkin.