How should RvS be used?
Optimal use involves using it only when at exactly 4 CP. This will mean that not all of your finishers will benefit from it, as sometimes Glyph of SS will take you straight from 3 to 5. However, this is the only way to be sure that you never waste combo points, and current estimates show the damage lost from wasting combo points is more than you gain from being able to do every finisher with RvS up.