Hello there. I'm thinking of getting a High Step, since Cathe uses it in so many of her workouts. I'm trying to figure out whether I can get away with just ordering the High Step "topper" and using my 4 risers, or if I should shell out the extra cash for extra risers. Anyone think having only 4 risers won't be enough to get the most out of the workouts where the High Step is used? I appreciate any input.