You’re being very naughty, Trent.
The report says the plan was to refuel at Bourke. (You have read the report, haven’t you? That’s the second time I’ve asked that question…)
The ‘best range’ speed for CCQ is what it is (was). It is (was) determined by the laws of physics, and therefore the outcome is the same, whether or not the planned destination is Charleville, Chicago or Chittagong.
Arguing about what the best range speed for CCQ may have been, and whether it’s a good idea for CCQ to have been operated at that speed, seems to me to be a pointless exercise.