Basically, the choreo sequence is the replacement for the ladies' spiral sequence and the men's second step sequence. It is not given any levels--only GOE--because it was created in order to allow more freedom of choreographic expression. The most important things to remember when choreographing a choreo sequence are to make sure it expresses the music and make sure it covers the entire ice surface (the width of the rink if circular, or red end line to red end line if straight line or serpentine shape). And yes, for the ladies, to include at least one spiral of any length.