I have a lot of experience with this. My wife and daughter are both right handed and have dominant left eyes. I taught them both to shoot left handed. I have found that many people have trouble with eye dominance at least some of the time. My left eye will take over on me if I am tired, the light is poor and or the target is crossing from right to left. Low 3 is a problem for me at times. I find that if I ride a target, meaning that I swing longer then usual, the left eye will take over. The tape on the lens works well. You can start by putting some grease on your finger, mounting your gun and touching the lens exactly where you see the front bead. Once you find the right spot a small piece of frosted tape will work. At first it will be all you see but with practice it will seem to go away. Switching to left handed might end up easier than you think, with lots of shooting. In shotgun shooting the eyes are everything. Good luck and let us know how you make out, Shotgunner