OBSTACLE_DISTANCE how?

I want to implement sending OBSTACLE_DISTANCE messages over mavros to ardurover so it can handle bendy-line and other built-in obstacle avoidance algorithms. I use a jetson TX1 running ROS and zed camera OR hokoyu lidar to generate laser scan. I can communicate using mavros/mavlink but even after reading every blog I could find I am not sure how to send and make the fcu use OBSTACLE_DISTANCE. I read somewhere about a 72 point limit. That is not a problem - I can always map in python and publish a condensed array. Obviously generating DISTANCE_SENSOR message is not useful as it is only one reading, although,I suppose I could take the laser scan and send out 10 DISTANCE_SENSOR corresponding to specific angles. Possible ?
Any help much appreciated.