Chain swords (any variety) are about the hardiest foreground available. They'll do just fine under 1.5-2wpg normal ouputs. The tough part is keeping them rooted. They usually arrive to the hobbyists hands with badly damaged or missing roots. Try and get some from a hobbyists for an easier time in that respect
Your light is more than adequate, but they'll explode under PC's. You'll be trading in no time 8)