Its tap fed, not had a proper go at gravity fed, might have a practise over wknd. Reason being, it depends on the tap pressure feeding my machine. So the above job i used a turbo nozzel (lol i enjoy using turbo nozzels, never get tired of using it.) And from start to finish, including soft wash afterwards, probably about an hr.
The videos and pictures on either of my sites (however the facebook page shows most) are with same pressure washer.