How a Back Stance Should Look

Does your back stance need a little work?

Probably.

Here is a nice example of a back stance. Notice the foot alignment (90 degrees), and how big the stance is. The back leg is bent nicely and the front leg is nearly straight.

You will also notice that he is doing a twin knife hand. We do this at lot. It's in Heian Shodan, Nidan, and Yodan. His hands are a bit far forward for my tastes. I like the chamber to stop palm of hand at body mid line. I would also pull the striking hand back with the elbow roughly one fist width from the ribs. This is a pretty classic over shut when done with great force.

Study this picture and try to get your back stance to look like this. not only when you pose, but moving quicky into the stance.