Keeping them at or near the same distance as your shoulders is ideal, though you may have to work up to that ability. With practice, you will be able to hold this posture longer and longer. Coming out of the posture should be done by dropping the hands to the floor for support and lowering the legs above the head to a 45 degree angle. Next, gently and slowly roll the spine down, feeling each vertebra as it makes contact with the floor. It is suggested that a counter asana be performed after Sarvangasana, such as the Fish Posture.
Many people get into yoga in order to relax.
Yoga has been around for centuries, and in all that time, one main theme is repeated is that the practice of asanas involves very powerful forces, spiritual and physical. It is discouraging to see a great class or video that ends without proper attention to the final relaxation. It is vitally important, and equally important to relax between asanas. An ideal class has a long final relaxation of at least five to ten minutes. Ideally, the yogi should stay through the class to the end.