Brass or Zinc for me. Zinc strikes me as easier to work with, however. Trick with either of them, though, is finding the right context to use them in. Were you to just walk up to a someone in a bar and trigger lust, for instance, I'd venture to guess that you're more likely to get crucified than 'lucky'. Small pushes on their emotions while flirting with them, however, stand a far better chance of success. The same idea applies to a riot. You don't just walk up to someone and say "get angry", you'd have to give them reason to be angry and use your power in conjunction with it. Same applies with calming effects. You'd be best served to mask your attempts with activities that one would expect those emotions to rise/drop with. It's a subtle touch that sells it.