One thing one may perhaps want to note is that mirroring the kind of right-handed shooting position where the support hand is held fairly straight and along the rifle can result in hot brass bouncing off the support arm when shooting left-handed. Me personally, I find that annoying, at least if I am only wearing a short sleeved shirt. So that may have an effect on how a lefty may want to build their shooting position, possibly. Or perhaps not, I'm not exactly an expert in this topic.