Well, I'm not enough of an expert to know if you need left helical because you shoot left handed, but I really can't see it making any difference at all. My gut instinct is that I'd still go with right helical for two reasons. First, right wing feathers are much easier to get your hands on if you ever decide to try feathers. Second, and this may or may not make any difference, but right helical will turn the arrow opposite the threads on your FPs and BHs.