We did the Gibb in 2014 two adults, 03 rodeo towing a small cub, I worked on an average of 15 lts/ 100 km. We topped up at Imitje (may be open in 2016), Mt. Barrmet, Drysdale, Kalumbaroo, Drysdale, Kunnanura, not sure of figures but never had to use gerry cans apart from the Tanami, I hope this helps