gadd uses double strokes and triplet figures alot. try and experiment with these such as a doubles (rrllrrll etc) betwn hi-hat and snare- rr (hi-hat) ll (snare)- at high tempos, then add the bass on 1 or whenever. Also try triplet figures round the toms and bass e.g. rlbrlbrlb on two toms and bass...or lrb (on two toms n bass) followed by lrb (using high tom and snare) at high tempos.