Do both. SU in the morning to get you cleared, and fired up. And SC in the evening, for calming. Self-Concentration does the opening of the channels, so as you open the channels in each part of the body, you can also visualize that you are opening and clearing the front and back channels.
This would give you a "quick clear" that may or may not be as "thorough" as SU, but since you pair it with SU in the morning, both meditations would actually enhance one-another (even though you are doing them at "different times")
~Z