I was surprised by how easy this roll was. But then I have a low volume kayak. Plus I (had) a lot of flexibility at the time. The ease with which you can complete this roll is probably proportional to your ability to lie flat on your kayak’s aft deck. I know I am ready to do this roll when I can feel the deck on my head. It is critical to remain pressed against the back deck throughout this roll. Your body does not reach up to the water so your only righting moment is that created my your arm, hand and norsaq. Any body movement away from the center of rotation will slow down the roll and prevent the roll completing.
You can view the video and tutorial here.