Yee gee kim yung ma.
Just a few points i picked up working with Blair and in my own time about the correct position for kim yung ma.
When i learnt in the beginning i was told to keep the the feet touching, i have noticed that this is not so important, in fact, when i begin with my feet so close i find i have to adjust slightly when i have finished opening my stance. ( will come back to this point)
When you bend the knees at first, keep the back straight.
look straight ahead.
After turning the toes and heels out having opened the stance, take a few seconds to check the position.
a good method we found out was to let the arms hang loose by your sides. If your arms are natural falling onto your thighs , then you probably have the right position (for you). Also check where the fingers point down, there should be an imaginary line from your fingertips to the inside of your big toe.
This method should give you an indication that you have made the correct stance, for you.
Coming back to the earlier point, that i have to adjust to find MY stance. The stance will vary slightly from person to person, depending on hight, weight, mass, length of legs, length of body, flexibility etc. So take some time to check and make sure you are using the stance as it works best for you.
You can usually tell if you are doing it correctly because you should naturally sink into the stance, once you have a comfortable fit, next you should test your position after you have turned into the combat stance. Take time to find out what adjustments (if any) need to be made to make the combat stance as stable as the training stance.
Hope this helps, happy training.