I bet that gets greasy when it's hot...
I'm left handed right eye dominate and hard headed...I finally started using a dot kit by Decot and my shooting greatly improved.
http://www.sportglasses.com/cart/products/34/Decot%20Dots%20%282%20Magnetic%20Opaque%20Dots%20per%20Package%29.htm
I've also heard that you could take an erasable felt pen and draw lines about a quarter inch apart vertically and horizontally on the dominate eye lens and that will confuse your eye but not restrict your vision too much....I haven't personally tried it.
