I don't really see much of a use to will-o-wisp as it is, when you're faced with the choice of wisp or ray (but that's my opinion). I see you're using Rest though, so I'd go with Confuse Ray. The ray can buy you time to actually use Rest in tight situations. Curse will take damage from the opponent each turn anyway, so doesn't it seem like it does a good job taking the role of will-o-wisp? Idk, I'm fairly new to strategizing anyway (really, I've never really strategized before), but on my opinion I'd use confuse ray.