Currently, I do about 8 sets on my abs. 3xdecline sit ups, 3xleg raises, and then 2x V ups. I take about a 30 second break between each set. For decline sit ups and leg raises, I go very slow (4 seconds up, 4 seconds down) until failure. How should I do this differently with HST in terms of tempo, number of sets (2 seems so little), etc?