You might try to keep in mind the health aspects of sanchin. I used to use the feet pointing inward in my sanchin stance, but later changed it when I started training with Tony Sandoval in Fujian White Crane. He-Tony, told me that by turning in your feet, it's like you're being pulled at your waist in a downward 45' degree angle. While this is a good stance, it can have a negative affect on your heart. So, I learned to keep my feet pointing forward. Later on, I went back to the older stance, and yes I did feel the downward 45' degree tug at my waist, and I did tend to feel that my heart seemed to work harder than usual.
I'm not saying that this is true for everybody, but for me making that one change in foot posture did have an overall affect on my health.