With rolling gaps it's not always about how fast you're going when you take off it's about the power being produced at the crank, try adjusting your run up so you're pedalling towards the gap in one fluid motion rather than stop-starting.
I run 165 burns on my coust, 18 15 with a king on the rear, you certainly notice the difference in power but you do have to put a bit more in to get the static moves.