Sweet group, but Asbel would caution you regarding short drawing. It is often the begining of "Snap Shooting" which can lead to "Target Panic".
Your anchor can change, but make sure it is a real and unchanging anchor. I have seen guys use the tip of their nose as anchor points, but it was an anchor point. It is tough to beat the middle finger in the corner of the mouth, but ain't nothin etched in stone in this sport. If it works, stay with it.....