As a professional shooter with the same problem you have, here is the solution that I have used for almost 20 years. As mentioned, place a strip of transparent tape over the top half of the left lens of your glasses. Placement is important. To make sure it is positioned correctly, close your right eye and extend your arms like you are shooting. The tape should occlude everything past your wrist. If you can see your hands, then lower the tape, if you can't see your wrists, raise it. You should only need to do this with iron sights - not with optics. The tape allows you the benefit of binoucular peripheral vision and depth perception while eliminating the double front sight. You will find that shooting with both eyes open is much easier, faster and more consistent than closing one eye. BTW, this was a problem for me and I am not "cross eye dominant".
To find out which eye is dominant, extend both arms in front of you. Make a circle with your hands. Look through the circle and pick a small object. Focus on the object. While keeping perfect focus on the object, pull your hands closer and closer to your face until they touch it. Keep the object in clear focus and your hands will go to your dominant eye.