We took 21 days from Halls Creek to Wiluna. The fuel consumption is good because we managed our tyre pressures. With 15psi pressure, the dunes are easy, and the corrugations more bearable. Dunes were approached in 1st gear high range, stopping at the base of each, with very little low range work.
We did not have to back down dunes for 3 or 4 goes, because the tyres were at the right pressure.
Nothing affects fuel consumption more than several attempts at each dune.
Remember there is reliable fuel at Kunawarritji, but it is expensive.
240 L usage was from Billiluna to Wiluna, distance from Billiluna to the CSR turn-off at the Wiluna end was 1968km on the odometer.
We calculated fuel usage of around 20 L per hundred, and carried a total of 420 L, (210 L times 2) after topping up with 104 L at Kunawarritji.
Better to over estimate your fuel than underestimate it. We also travelled very light, basically if it did not fit in the tray it did not come (apart from spare tyre casing on roof rack) and did not tow a camper trailer. We also travelled early in the season and had no rain delays and good conditions.